Arabic verbs

Arabic verbs (فِعْل fiʻl; pl. أَفْعَال afʻāl), like the verbs in other Semitic languages, and the entire vocabulary in those languages, are based on a set of two, three, four and also five (but mainly three) consonants called a root (triliteral or quadriliteral according to the number of consonants). The root communicates the basic meaning of the verb, e.g. k-t-b 'write', q-r-ʼ 'read', ʼ-k-l 'eat'. Changes to the vowels in between the consonants, along with prefixes or suffixes, specify grammatical functions such as person, gender, number, tense, mood, and voice. An example from the root k-t-b 'write':

Active			Passive
Past	Present	Imperative	Past	Present
كَتَبَ kataba 'he wrote'	يَكْتُبُ yaktubu 'he writes'	أُكْتُبْ uktub 'write!' (sg.)	كُتِبَ kutiba 'it was written'	يُكْتَبُ yuktabu 'it is written'
كَتَّبَ kattaba 'he caused to write'	يُكَتِّبُ yukattibu 'he causes to write'	كَتِّبْ kattib 'cause to write!' (sg.)	كُتِّبَ kuttiba 'he was made to write'	يُكَتِّبُ yukattabu 'he is made to write'
تَكَاتَبَ takātaba 'he corresponded (with someone)'	يَتَكَاتَبُ yatakātabu 'he corresponds (with someone)'	تَكَاتَبْ takātab 'correspond (with someone)!' (sg.)	تُكُوتِبَ tukūtiba 'he was corresponded (with)'	يُتَكَاتَبُ yutakātabu 'he is corresponded (with)'

Various categories are marked on verbs:

• Three tenses (present, past; future tense is indicated by the prefix sa- or the particle sawfa and the present tense).
• Two voices (active, passive)
• Two genders (masculine, feminine)
• Three persons (first, second, third)
• Three numbers (singular, dual, plural)
• Six moods in the non-past only (indicative, subjunctive, jussive, imperative, and, only in Classical Arabic, short and long energetics)
• Nineteen forms, the derivational systems indicating derivative concepts such as intensive, causative, reciprocal, reflexive, frequentative etc. For each form, there is also an active and a passive participle (both adjectives, declined through the full paradigm of gender, number, case and state) and a verbal noun (declined for case; also, when lexicalized, may be declined for number).

Weakness is an inherent property of a given verb determined by the particular consonants of the verb root (corresponding to a verb conjugation in Classical Latin and other European languages), with five main types of weakness and two or three subtypes of each type.

Arabic grammarians typically use the root f-ʻ-l to indicate the particular shape of any given element of a verbal paradigm. As an example, the form yutakātabu 'he is corresponded (with)' would be listed generically as yutafāʻalu, specifying the generic shape of a strong Form VI passive verb, third-person masculine singular present indicative.

The maximum possible total number of verb forms derivable from a root — not counting participles and verbal nouns — is approximately 13 person/number/gender forms; times 7.385 tense/mood combinations, counting the sa- future (since the moods are active only in the present tense, and the imperative has only 5 of the 13 paradigmatic forms); times 17 form/voice combinations (since forms IX, XI-XV exist only for a small number of stative roots, and form VII cannot normally form a passive), for a total of 1,632. Each of these has its own stem form, and each of these stem forms itself comes in numerous varieties, according to the weakness (or lack thereof) of the underlying root.

Inflectional categories

Each particular lexical verb is specified by four stems, two each for the active and passive voices. In a particular voice, one stem (the past stem) is used for the past tense, and the other (the non-past stem) is used for the present and future tenses, along with non-indicative moods, e.g. subjunctive and imperative. The past and non-past stems are sometimes also called the perfective stem and imperfective stem, respectively, based on a traditional misinterpretation of Arabic stems as representing grammatical aspect rather than grammatical tense. (Although there is still some disagreement about the interpretation of the stems as tense or aspect, the dominant current view is that the stems simply represent tense, sometimes of a relative rather than absolute nature. There are some unusual usages of the stems in certain contexts that were once interpreted as indicating aspectual distinctions, but are now thought to simply be idiosyncratic constructions that do not neatly fit into any aspectual paradigm.)

To the past stem, suffixes are added to mark the verb for person, number and gender, while to the non-past stem, a combination of prefixes and suffixes are added. (Very approximately, the prefixes specify the person and the suffixes indicate number and gender.) A total of 13 forms exist for each of the two stems, specifying person (first, second or third); number (singular, dual or plural); and gender (masculine or feminine).

There are six separate moods in the non-past: indicative, imperative, subjunctive, jussive, short energetic and long energetic. The moods are generally marked by suffixes. When no number suffix is present, the endings are -u for indicative, -a for subjunctive, no ending for imperative and jussive, -an for shorter energetic, -anna for longer energetic. When number suffixes are present, the moods are either distinguished by different forms of the suffixes (e.g. -ūna for masculine plural indicative vs. -ū for masculine plural subjunctive/imperative/jussive), or not distinguished at all. The imperative exists only in the second person and is distinguished from the jussive by the lack of the normal second-person prefix ta-/tu-.

The third person masculine singular past tense form serves as the "dictionary form" used to identify a verb, similar to the infinitive in English. (Arabic has no infinitive.) For example, the verb meaning 'write' is often specified as kataba, which actually means 'he wrote'. This indicates that the past-tense stem is katab-; the corresponding non-past stem is -ktub-, as in yaktubu 'he writes'.

Derivational categories, conjugations

The system of verb conjugations in Arabic is quite complicated, and is formed along two axes. One axis, known as the form (described as "Form I", "Form II", etc.), is used to specify grammatical concepts such as causative, intensive, reciprocal, passive or reflexive, and involves varying the stem form. The other axis, known as the weakness, is determined by the particular consonants making up the root. For example, defective (or third-weak) verbs have a w or y as the last root consonant (e.g. r-m-y 'throw', d-ʻ-w 'call'), and doubled verbs have the second and third consonants the same (e.g. m-d-d 'extend'). These "weaknesses" have the effect of inducing various irregularities in the stems and endings of the associated verbs.

Examples of the different forms of a sound verb (i.e. with no root weaknesses), from the root k-t-b 'write' (using ḥ-m-r 'red' for Form IX, which is limited to colors and physical defects):

Form	Past	Meaning	Non-past	Meaning
I	kataba	'he wrote'	yaktubu	'he writes'
II	kattaba	'he made (someone) write'	yukattibu	'he makes (someone) write'
III	kātaba	'he corresponded with, wrote to (someone)'	yukātibu	'"he corresponds with, writes to (someone)'
IV	ʼaktaba	'he dictated'	yuktibu	'he dictates'
V	takattaba	nonexistent	yatakattabu	nonexistent
VI	takātaba	'he corresponded (with someone, esp. mutually)'	yatakātabu	'he corresponds (with someone, esp. mutually)'
VII	inkataba	'he subscribed'	yankatibu	'he subscribes'
VIII	iktataba	'he copied'	yaktatibu	'he copies'
IX	iḥmarra	'he turned red'	yaḥmarru	'he turns red'
X	istaktaba	'he asked (someone) to write'	yastaktibu	'he asks (someone) to write'

The main types of weakness are as follows:

Main weakness varieties for Form I, with verbs in the active indicative

Weakness	Root	Past, 3Sg Masc	Past, 1Sg	Present, 3Sg Masc	Present, 3Pl Fem
Sound (Non-Weak)	k-t-b 'to write'	kataba	katabtu	yaktubu	yaktubna
Assimilated (First-Weak), W	w-j-d 'to find'	wajada	wajadtu	yajidu	yajidna
Assimilated (First-Weak), Y	y-b-s 'to dry'	yabisa	yabistu	yaybasu	yaybasna
Hollow (Second-Weak), W	q-w-l 'to say'	qāla	qultu	yaqūlu	yaqulna
Hollow (Second-Weak), Y	s-y-r 'to travel, go'	sāra	sirtu	yasīru	yasirna
Defective (Third-Weak), W	d-ʻ-w 'to call'	daʻā	daʻawtu	yadʻū	yadʻūna
Defective (Third-Weak), Y	r-m-y 'to throw'	ramā	ramaytu	yarmī	yarmīna
Doubled	m-d-d 'to extend'	madda	madadtu	yamuddu	yamdudna

Regular verb conjugation for person-number, tense-aspect-mood, and participles

In Arabic the grammatical person and number as well as the mood are designated by a variety of prefixes and suffixes. The following table shows the paradigm of a regular sound Form I verb, kataba (كتب) 'to write'. Final short vowels that are part of the formal paradigm but often omitted in speech are given in parentheses. This includes most final short vowels; but not in feminine plural -na, and not normally in past tense second person feminine singular -ti.

Paradigm of a regular Form I Arabic verb, kataba (yaktubu) 'to write'

			Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Active	Singular
	1st		katab-tu	a-ktub-u	a-ktub-a	a-ktub	a-ktub-anna	a-ktub-an	–
			كَتَبْتُ‎	أَكْتُبُ‎	أَكْتُبَ‎	أَكْتُبْ‎	أَكْتُبَنَّ‎	أَكْتُبَنْ‎	–
	2nd	masculine	katab-ta	ta-ktub-u	ta-ktub-a	ta-ktub	ta-ktub-anna	ta-ktub-an	u-ktub
			كَتَبْتَ‎	تَكْتُبُ‎	تَكْتُبَ‎	تَكْتُبْ‎	تَكْتُبَنَّ‎	تَكْتُبَنْ‎	اُكْتُبْ‎
		feminine	katab-ti	ta-ktub-īna	ta-ktub-ī	ta-ktub-ī	ta-ktub-inna	ta-ktub-in	u-ktub-ī
			كَتَبْتِ‎	تَكْتُبِينَ‎	تَكْتُبِي‎	تَكْتُبِي‎	تَكْتُبِنَّ‎	تَكْتُبِنْ‎	اُكْتُبِي‎
	3rd	masculine	katab-a	ya-ktub-u	ya-ktub-a	ya-ktub	ya-ktub-anna	ya-ktub-an	–
			كَتَبَ‎	يَكْتُبُ‎	يَكْتُبَ‎	يَكْتُبْ‎	يَكْتُبَنَّ‎	يَكْتُبَنْ‎	–
		feminine	katab-at	ta-ktub-u	ta-ktub-a	ta-ktub	ta-ktub-anna	ta-ktub-an	–
			كَتَبَتْ‎	تَكْتُبُ‎	تَكْتُبَ‎	تَكْتُبْ‎	تَكْتُبَنَّ‎	تَكْتُبَنْ‎	–
	Dual
	2nd	masculine & feminine	katab-tumā	ta-ktub-āni	ta-ktub-ā	ta-ktub-ā	ta-ktub-ānni	–	u-ktub-ā
			كَتَبْتُمَا‎	تَكْتُبَانِ‎	تَكْتُبَا‎	تَكْتُبَا‎	تَكْتُبَانِّ‎	–	اُكْتُبَا‎
	3rd	masculine	katab-ā	ya-ktub-āni	ya-ktub-ā	ya-ktub-ā	ya-ktub-ānni	–	–
			كَتَبَا‎	يَكْتُبَانِ‎	يَكْتُبَا‎	يَكْتُبَا‎	يَكْتُبَانِّ‎	–	–
		feminine	katab-atā	ta-ktub-āni	ta-ktub-ā	ta-ktub-ā	ta-ktub-ānni	–	–
			كَتَبَتَا‎	تَكْتُبَانِ‎	تَكْتُبَا‎	تَكْتُبَا‎	تَكْتُبَانِّ‎	–	–
	Plural
	1st		katab-nā	na-ktub-u	na-ktub-a	na-ktub	na-ktub-anna	na-ktub-an	–
			كَتَبْنَا‎	نَكْتُبُ‎	نَكْتُبَ‎	نَكْتُبْ‎	نَكْتُبَنَّ‎	نَكْتُبَنْ‎	–
	2nd	masculine	katab-tum	ta-ktub-ūna	ta-ktub-ū	ta-ktub-ū	ta-ktub-unna	ta-ktub-un	u-ktub-ū
			كَتَبْتُمْ‎	تَكْتُبُونَ‎	تَكْتُبُوا‎	تَكْتُبُوا‎	تَكْتُبُنَّ‎	تَكْتُبُنْ‎	اُكْتُبُوا‎
		feminine	katab-tunna	ta-ktub-na	ta-ktub-na	ta-ktub-na	ta-ktub-ānni	–	u-ktub-na
			كَتَبْتُنَّ‎	تَكْتُبْنَ‎	تَكْتُبْنَ‎	تَكْتُبْنَ‎	تَكْتُبَانِّ‎	–	اُكْتُبْنَ‎
	3rd	masculine	katab-ū	ya-ktub-ūna	ya-ktub-ū	ya-ktub-ū	ya-ktub-unna	ya-ktub-un	–
			كَتَبُوا‎	يَكْتُبُونَ‎	يَكْتُبُوا‎	يَكْتُبُوا‎	تَكْتُبُنِّ‎	تَكْتُبُنْ‎	–
		feminine	katab-na	ya-ktub-na	ya-ktub-na	ya-ktub-na	ya-ktub-ānni	–	–
			كَتَبْنَ‎	يَكْتُبْنَ‎	يَكْتُبْنَ‎	يَكْتُبْنَ‎	تَكْتُبَانِّ‎	–	–
Passive	Singular
	1st		kutib-tu	u-ktab-u	u-ktab-a	u-ktab	u-ktab-anna	u-ktab-an	–
			كُتِبْتُ‎	أُكْتَبُ‎	أُكْتَبَ‎	أُكْتَبْ‎	أُكْتَبَنَّ‎	أُكْتَبَنْ‎	–
	2nd	masculine	kutib-ta	tu-ktab-u	tu-ktab-a	tu-ktab	tu-ktab-anna	tu-ktab-an	–
			كُتِبْتَ‎	تُكْتَبُ‎	تُكْتَبَ‎	تُكْتَبْ‎	تُكْتَبَنَّ‎	تُكْتَبَنْ‎	–
		feminine	kutib-ti	tu-ktab-īna	tu-ktab-ī	tu-ktab-ī	tu-ktab-inna	tu-ktab-in	–
			كُتِبْتِ‎	تُكْتَبِينَ‎	تُكْتَبِي‎	تُكْتَبِي‎	تُكْتَبِنَّ‎	تُكْتَبِنْ‎	–
	etc.
Nominal	Active Participle				Passive Participle			Verbal Noun
	kātib				maktūb			katb, kitbah, kitābah
	كَاتِب‎				مَكْتُوب‎			كَتْب، كِتْبَة، كِتَابَة‎

The initial vowel in the imperative (which is elidable) varies from verb to verb, as follows:

• The initial vowel is u if the stem begins with two consonants and the next vowel is u or ū.
• The initial vowel is i if the stem begins with two consonants and the next vowel is anything else.
• There is no initial vowel if the stem begins with one consonant.

In unvocalised Arabic, katabtu, katabta, katabti and katabat are all written the same: كتبت. Forms katabtu and katabta (and sometimes even katabti) can be abbreviated to katabt in spoken Arabic and in pausa, making them also sound the same.

ا (alif) in final ـُوا (-ū) is silent.

Tense

There are three tenses in Arabic: the past tense (اَلْمَاضِي al-māḍī), the present tense (اَلْمُضَارِع al-muḍāriʻ) and the future tense. The future tense in Classical Arabic is formed by adding either the prefix سَـ‎ sa- or the separate word سَوْفَ‎ sawfa onto the beginning of the present tense verb, e.g. سَيَكْتُبُ sa-yaktubu or سَوْفَ يَكْتُبُ sawfa yaktubu 'he will write'.

In some contexts, the tenses represent aspectual distinctions rather than tense distinctions. The usage of Arabic tenses is as follows:

• The past tense often (but not always) specifically has the meaning of a past perfective, i.e. it expresses the concept of 'he did' as opposed to 'he was doing'. The latter can be expressed using the combination of the past tense of the verb كَانَ kāna 'to be' with the present tense or active participle, e.g. كَانَ يَكْتُبُ kāna yaktubu or كَانَ كَاتِبٌ kāna kātibun 'he was writing'. there are some special verbs known as "compound verbs" that can express many grammatical aspects such as Inchoative, Durative etc., for example bada’a yulfitu nnażara means "It started to attract attention" which bada’a conveys the meaning of "to start doing something (in the past)"
• The two tenses can be used to express relative tense (or in an alternative view, grammatical aspect) when following other verbs in a serial verb construction. In such a construction, the present tense indicates time simultaneous with the main verb, while the past tense indicates time prior to the main verb. (Or alternatively, the present tense indicates the imperfective aspect while the past tense indicates the perfective aspect.)

In all but Form I, there is only one possible shape for each of the past and non-past stems for a given root. In Form I, however, different verbs have different shapes. Examples:

• كَتَبَ يَكْتُبُ kataba yaktubu 'write'
• كَسِبَ يَكْسِبُ kasaba yaksibu 'earn'
• قَرَأَ يَقْرَأُ qaraʼa yaqraʼu 'read'
• قَدِمَ يَقْدَمُ qadima yaqdamu 'turn'
• كَبُرَ يَكْبُرُ kabura yakburu 'become big, grow up'

Notice that the second vowel can be any of a i u in both past and non-past stems. The vowel a occurs in most past stems, while i occurs in some (especially intransitive) and u occurs only in a few stative verbs (i.e. whose meaning is 'be X' or 'become X' where X is an adjective). The most common patterns are:

• past: a; non-past: u or i
• past: a, non-past: a (when the second or third root consonant is a "guttural," i.e. one of ʼ ʻ h ḥ)
• past: i; non-past: a
• past: u; non-past: u

Mood

There are three moods (حَالَات ḥālāt "cases", sg. حَالَة‎ ḥālah), whose forms are derived from the imperfective stem: the indicative mood (مَرْفُوع‎ marfūʻ), usually ending in u; the subjunctive (مَنْصُوب‎ manṣūb), usually ending in a; and the jussive (مَجْزُوم‎ majzūm), with no ending. In less formal Arabic and in spoken dialects, the final vowels of the indicative and subjunctive are not pronounced, making them identical to jussive.

The imperative (صِيغَة اَلْأَمْر ṣīghat al-amr) (positive, only 2nd person) is formed by dropping the verbal prefix from the imperfective jussive stem, e.g. قَدِّم qaddim 'present!'. If the result starts with two consonants followed by a vowel (a or i), an elidible alif is added to the beginning of the word, usually pronounced as "i", e.g. اِغْسِلْ ighsil 'wash!' or اِفْعَل ifʻal 'do!' if the present form vowel is u, then the alif is also pronounced as u, e.g. أُكْتُب uktub 'write!'. Negative imperatives are formed from the jussive.

The exception to the above rule is the form (or stem) IV verbs. In these verbs a non-elidible alif pronounced as a- is always prefixed to the imperfect jussive form, e.g. أرسل arsil "send!", أضف aḍif 'add!'.

The subjunctive is used in subordinate clauses after certain conjunctions. The jussive is used in negation, in negative imperatives, and in the hortative li+jussive. For example: 2. sg. m.:

• imperfect indicative tafʻalu 'you are doing'
• subjunctive an tafʻala 'that you do'
• jussive lā tafʻal its meaning is dependent upon the prefix which attaches to it; in this case, it means 'may you do not do!'
• short energetic tafʻalan its meaning is dependent upon the prefix which attaches to it; if the prefix is "li" it means 'you should do'
• long energetic tafʻalanna it has more emphasis than the short energetic, its meaning is dependent upon the prefix which attaches to it; if the prefix is "li" it means 'you must do'
• imperative ifʻal 'do!'.

Voice

Arabic has two verbal voices (صِيغَات sīghāt "forms", sg. صِيغَة sīghah), active (صِيغَة اَلْمَعْلُوم ṣīghat al-maʻlūm), and passive (صِيغَة اَلْمَجْهُول ṣīghat al-majhūl). The passive voice is expressed by a change in vocalization. For example:

• active فَعَلَ faʻala 'he did', يَفْعَلُ yafʻalu 'he is doing'
• passive فُعِلَ fuʻila 'it was done', يُفْعَلُ yufʻalu 'it is being done'

Thus, the active and passive forms are spelled identically in Arabic; only their vowel markings differ.

Weak roots

Roots containing one or two of the radicals w (wāw), y (yāʼ ) or ʼ (hamzah) often lead to verbs with special phonological rules because these radicals can be influenced by their surroundings. Such verbs are called "weak" (verba infirma, 'weak verbs') and their paradigms must be given special attention. In the case of hamzah, these peculiarities are mainly orthographical, since hamzah is not subject to elision (the orthography of hamzah and alif is unsystematic due to confusion in early Islamic times). According to the position of the weak radical in the root, the root can be classified into four classes: first weak, second weak, third weak and doubled, where both the second and third radicals are identical. Some roots fall into more than one category at once.

Doubled roots

The following shows a paradigm of a typical Form I doubled verb madda (yamuddu) 'to extend', parallel to verbs of the faʻala (yafʻulu) type. See notes following the table for explanation.

Paradigm of a form I doubled Arabic verb, madda (yamuddu) "to extend"

		Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Singular
1st		madad-tu	a-mudd-u	a-mudd-a	a-mudd-a, ʼa-mudd-i, ʼa-mdud	a-mudd-anna	a-mudd-an	–
		مَدَدْتُ	أَمُدُّ	أَمُدَّ	أَمُدَّ, أَمُدِّ, أَمْدُدْ	أَمُدَّنَّ	ْأَمُدَّن	–
2nd	masculine	madad-ta	ta-mudd-u	ta-mudd-a	ta-mudd-a, ta-mudd-i, ta-mdud	ta-mudd-anna	ta-mudd-an	mudd-a, mudd-i, u-mdud
		مَدَدْتَ	تَمُدُّ	تَمُدَّ	تَمُدَّ, تَمُدِّ, تَمْدُدْ	تَمُدَّنَّ	ْتَمُدَّن	مُدَّ, مُدِّ, اُمْدُدْ
	feminine	madad-ti	ta-mudd-īna	ta-mudd-ī	ta-mudd-ī	ta-mudd-inna	ta-mudd-in	mudd-ī
		مَدَدْتِ	تَمُدِّينَ	تَمُدِّي	تَمُدِّي	تَمُدِّنَّ	ْتَمُدِّن	مُدِّي
3rd	masculine	madd-a	ya-mudd-u	ya-mudd-a	ya-mudd-a, ya-mudd-i, ya-mdud	ya-mudd-anna	ya-mudd-an	–
		مَدَّ	يَمُدُّ	يَمُدَّ	يَمُدَّ, يَمُدِّ, يَمْدُدْ	يَمُدَّنَّ	ْيَمُدَّن	–
	feminine	madd-at	ta-mudd-u	ta-mudd-a	ta-mudd-a, ta-mudd-i, ta-mdud	ta-mudd-anna	ta-mudd-an	–
		مَدَّتْ	تَمُدُّ	تَمُدَّ	تَمُدَّ, تَمُدِّ, تَمْدُدْ	تَمُدَّنَّ	ْتَمُدَّن	–
Dual
2nd	masculine & feminine	madad-tumā	ta-mudd-āni	ta-mudd-ā	ta-mudd-ā	ta-mudd-ānni	–	mudd-ā
		مَدَدْتُمَا	تَمُدَّانِ	تَمُدَّا	تَمُدَّا	تَمُدَّانِّ	–	مُدَّا
3rd	masculine	madd-ā	ya-mudd-āni	ya-mudd-ā	ya-mudd-ā	ya-mudd-ānni	–	–
		مَدَّا	يَمُدَّانِ	يَمُدَّا	يَمُدَّا	يَمُدَّانِّ	–	–
	feminine	madd-atā	ta-mudd-āni	ta-mudd-ā	ta-mudd-ā	ta-mudd-ānni	–	–
		مَدَّتَا	تَمُدَّانِ	تَمُدَّا	تَمُدَّا	تَمُدَّانِّ	–	–
Plural
1st		madad-nā	na-mudd-u	na-mudd-a	na-mudd-a, na-mudd-i, na-mdud	na-mudd-anna	na-mudd-an	–
		مَدَدْنَا	نَمُدُّ	نَمُدَّ	نَمُدَّ, نَمُدِّ, نَمْدُدْ	نَمُدَّنَّ	ْنَمُدَّن	–
2nd	masculine	madad-tum	ta-mudd-ūna	ta-mudd-ū	ta-mudd-ū	ta-mudd-unna	ta-mudd-un	mudd-ū
		مَدَدْتُمْ	تَمُدُّونَ	تَمُدُّوا	تَمُدُّوا	تَمُدُّنَّ	ْتَمُدُّن	مُدُّوا
	feminine	madad-tunna	ta-mdud-na	ta-mdud-na	ta-mdud-na	ta-mdud-nānni	–	umdud-na
		مَدَدْتُنَّ	تَمْدُدْنَ	تَمْدُدْنَ	تَمْدُدْنَ	تَمْدُدْنَانِّ	–	اُمْدُدْنَ
3rd	masculine	madd-ū	ya-mudd-ūna	ya-mudd-ū	ya-mudd-ū	ya-mudd-unna	ya-mudd-un	–
		مَدُّوا	يَمُدُّونَ	يَمُدُّوا	يَمُدُّوا	يَمُدُّنَّ	ْيَمُدُّن	–
	feminine	madad-na	ya-mdud-na	ya-mdud-na	ya-mdud-na	ya-mdud-nānni	–	–
		مَدَدْنَ	يَمْدُدْنَ	يَمْدُدْنَ	يَمْدُدْنَ	يَمْدُدْنَانِّ	–	–

All doubled verbs are conjugated in a parallel fashion. The endings are for the most part identical to those of strong verbs, but there are two stems (a regular and a modified) in each of the past and non-past. The regular stems are identical to the stem forms of sound verbs, while the modified stems have the two identical consonants pulled together into a geminate consonant and the vowel between moved before the geminate. In the above verb madda (yamuddu) 'to extend' (s.th.), the past stems are madad- (regular), madd- (modified), and the non-past stems are mdud- (regular), mudd- (modified). In the table, places where the regular past stem occurs are in silver, and places where the regular non-past stem occurs are in gold; everywhere else, the modified stem occurs.

No initial vowel is needed in most of the imperative forms because the modified non-past stem does not begin with two consonants.

The concept of having two stems for each tense, one for endings beginning with vowels and one for other endings, occurs throughout the different kinds of weaknesses.

Following the above rules, endingless jussives would have a form like tamdud, while the corresponding indicatives and subjunctives would have forms like tamuddu, tamudda. As a result, for the doubled verbs in particular, there is a tendency to harmonize these forms by adding a vowel to the jussives, usually a, sometimes i. These are the only irregular endings in these paradigms, and have been indicated in boldface. The masculine singular imperative likewise has multiple forms, based on the multiple forms of the jussive.

The are various types of doubled Form I verbs:

Modified past stem (3rd sing. masc.)	Regular past stem (3rd plur. fem.)	Modified non-past stem (3rd sing. masc.)	Regular non-past stem (3rd plur. fem.)	Meaning	Sound verb parallel
madd-a	madad-na	ya-mudd-u	ya-mdud-na	'to extend'	faʻala (yafʻulu)
tamm-a	tamam-na	ya-timm-u	ya-tmim-na	'to finish'"	faʻala (yafʻilu)
ẓall-a	ẓalil-na	ya-ẓall-u	ya-ẓlal-na	'to remain'	faʻila (yafʻalu)

Assimilated (first-weak) roots

Most first-weak verbs have a w as their first root. These verbs are entirely regular in the past tense. In the non-past, the w drops out, leading to a shorter stem (e.g. wajada (yajidu) 'to find'), where the stem is -jid- in place of a longer stem like -jlid- from the verb jalada (yajlidu) 'to whip, flog'. This same stem is used throughout, and there are no other irregularities except for the imperative, which has no initial vowel, consistent with the fact that the stem for the imperative begins with only one consonant.

The are various types of assimilated (first-weak) Form I verbs:

Past stem (3rd sing. masc.)	Non-past stem (3rd sing. masc.)	Imperative (masc. sing.)	Meaning	Sound verb parallel
wajad-a	yajid-u	jid	'to find'	faʻala (yafʻilu)
warith-a	yarith-u	rith	'to inherit'	faʻila (yafʻilu) (rare normally, but in assimilated verbs, rather more common than faʻila (yafʻalu))
waḍaʻ-a	yaḍaʻ-u	ḍaʻ	'to put'	faʻala (yafʻalu)
wajil-a	yawjal-u	ījal	'to be scared'	faʻila (yafʻalu) (rare case where w is preserved in non-past)
yasar-a	yaysir-u	īsir	'to be simple'	faʻala (yafʻilu) (y is normally preserved in non-past)
yabis-a	yaybas-u	ības	'to be/become dry'	faʻila (yafʻalu) (y is normally preserved in non-past)
wadd-a (wadid-tu)	yadd-u	īdad	'to want to; to love'	faʻila (yafʻalu) (also a doubled verb)
waliy-a	yalī	li	'to protect'	faʻila (yafʻilu) (also a defective verb)

Hollow (second-weak) roots

The following shows a paradigm of a typical Form I hollow (second-weak) verb qāla (qultu, yaqūlu) 'to say', parallel to verbs of the faʻala (yafʻulu) type. See notes following the table for explanation.

Paradigm of a hollow (second-weak) Arabic verb, qāla (qultu, yaqūlu) 'to say'

		Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Singular
1st		qul-tu	a-qūl-u	a-qūl-a	a-qul	a-qūl-anna	a-qūl-an	–
		قُلْتُ	ُأَقُول	َأَقُول	ْأَقُل	أَقُولَنَّ	ْأَقُولَن	–
2nd	masculine	qul-ta	ta-qūl-u	ta-qūl-a	ta-qul	ta-qūl-anna	ta-qūl-an	qul
		قُلْتَ	ُتَقُول	َتَقُول	ْتَقُل	تَقُولَنَّ	ْتَقُولَن	قُلْ
	feminine	qul-ti	ta-qūl-īna	ta-qūl-ī	ta-qūl-ī	ta-qūl-inna	ta-qūl-in	qūl-ī
		قُلْتِ	تَقُولِينَ	تَقُولِي	تَقُولِي	تَقُولِنَّ	ْتَقُولِن	قُولِي
3rd	masculine	qāl-a	ya-qūl-u	ya-qūl-a	ya-qul	ya-qūl-anna	ya-qūl-an	–
		قَالَ	ُيَقُول	َيَقُول	ْيَقُل	يَقُولَنَّ	ْيَقُولَن	–
	feminine	qāl-at	ta-qūl-u	ta-qūl-a	ta-qul	ta-qūl-anna	ta-qūl-an	–
		قَالَتْ	ُتَقُول	َتَقُول	ْتَقُل	تَقُولَنَّ	ْتَقُولَن	–
Dual
2nd	masculine & feminine	qul-tumā	ta-qūl-āni	ta-qūl-ā	ta-qūl-ā	ta-qūl-ānni	–	qūl-ā
		قُلْتُمَا	تَقُولَانِ	تَقُولَا	تَقُولَا	تَقُولَانِّ	–	قُولَا
3rd	masculine	qāl-ā	ya-qūl-āni	ya-qūl-ā	ya-qūl-ā	ya-qūl-ānni	–	–
		قَالَا	يَقُولَانِ	يَقُولَا	يَقُولَا	يَقُولَانِّ	–	–
	feminine	qāl-atā	ta-qūl-āni	ta-qūl-ā	ta-qūl-ā	ta-qūl-ānni	–	–
		قَالَتَا	تَقُولَانِ	تَقُولَا	تَقُولَا	تَقُولَانِّ	–	–
Plural
1st		qul-nā	na-qūl-u	na-qūl-a	na-qul	na-qūl-anna	na-qūl-an	–
		قُلْنَا	ُنَقُول	َنَقُول	ْنَقُل	نَقُولَنَّ	ْنَقُولَن	–
2nd	masculine	qul-tum	ta-qūl-ūna	ta-qūl-ū	ta-qūl-ū	ta-qūl-unna	ta-qūl-un	qūl-ū
		قُلْتُمْ	تَقُولُونَ	تَقُولُوا	تَقُولُوا	تَقُولُنَّ	ْتَقُولُن	قُولُوا
	feminine	qul-tunna	ta-qul-na	ta-qul-na	ta-qul-na	ta-qul-nānni	–	qul-na
		قُلْتُنَّ	تَقُلْنَ	تَقُلْنَ	تَقُلْنَ	تَقُلْنَانِّ	–	قُلْنَ
3rd	masculine	qāl-ū	ya-qūl-ūna	ya-qūl-ū	ya-qūl-ū	ya-qūl-unna	ya-qūl-un	–
		قَالُوا	يَقُولُونَ	يَقُولُوا	يَقُولُوا	يَقُولُنَّ	ْيَقُولُن	–
	feminine	qul-na	ya-qul-na	ya-qul-na	ya-qul-na	ya-qul-nānni	–	–
		قُلْنَ	يَقُلْنَ	يَقُلْنَ	يَقُلْنَ	يَقُلْنَانِّ	–	–

All hollow (second-weak) verbs are conjugated in a parallel fashion. The endings are identical to strong verbs, but there are two stems (a longer and a shorter) in each of the past and non-past. The longer stem is consistently used whenever the ending begins with a vowel, and the shorter stem is used in all other circumstances. The longer stems end in a long vowel plus consonant, while the shorter stems end in a short vowel plus consonant. The shorter stem is formed simply by shortening the vowel of the long stem in all paradigms other than the active past of Form I verbs. In the active past paradigms of Form I, however, the longer stem always has an ā vowel, while the shorter stem has a vowel u or i corresponding to the actual second root consonant of the verb.

No initial vowel is needed in the imperative forms because the non-past stem does not begin with two consonants.

There are various types of Form I hollow verbs:

• qāla qulna (yaqūlu yaqulna) 'to say', formed from verbs with w as their second root consonant and parallel to verbs of the faʻala (yafʻulu) type
• sāra sirna (yasīru yasirna) 'to get going, to travel', formed from verbs with y as their second root consonant and parallel to verbs of the faʻala (yafʻilu) type
• khāfa khufna (yakhāfu yakhafna) 'to fear', formed from verbs with w as their second root consonant and parallel to verbs of the faʻila (yafʻalu) type
• nāma nimna (yanāmu yanamna) 'to sleep', formed from verbs with y as their second root consonant and parallel to verbs of the faʻila (yafʻalu) type

The passive paradigm of all Form I hollow verbs is as follows:

• qīla qilna (yuqālu yuqalna) 'to be said'

Defective (third-weak) roots

faʻā (yafʻī)

The following shows a paradigm of a typical Form I defective (third-weak) verb ramā (yarmī) 'to throw', parallel to verbs of the faʻala (yafʻilu) type. See notes following the table for explanation.

Paradigm of a defective (third-weak) y Arabic verb, ramā (yarmī) 'to throw'

		Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Singular
1st		ramay-tu	a-rmī	a-rmiy-a	a-rmi	a-rmiy-anna	a-rmiy-an	–
		رَمَيْتُ	أَرْمِي	َأَرْمِي	أَرْمِ	َأَرْمِيَنَّ	ْأَرْمِيَن	–
2nd	masculine	ramay-ta	ta-rmī	ta-rmiy-a	ta-rmi	ta-rmiy-anna	ta-rmiy-an	i-rmi
		رَمَيْتَ	تَرْمِي	َتَرْمِي	تَرْمِ	َتَرْمِيَنَّ	ْتَرْمِيَن	اِرْمِ
	feminine	ramay-ti	ta-rm-īna	ta-rm-ī	ta-rm-ī	ta-rm-inna	ta-rm-in	i-rm-ī
		رَمَيْتِ	تَرْمِينَ	تَرْمِي	تَرْمِي	َتَرْمِنَّ	ْتَرْمِن	اِرْمِي
3rd	masculine	ram-ā	ya-rmī	ya-rmiy-a	ya-rmi	ya-rmiy-anna	ya-rmiy-an	–
		رَمَی	يَرْمِي	َيَرْمِي	يَرْمِ	َيَرْمِيَنَّ	ْيَرْمِيَن	–
	feminine	ram-at	ta-rmī	ta-rmiy-a	ta-rmi	ta-rmiy-anna	ta-rmiy-an	–
		رَمَتْ	تَرْمِي	َتَرْمِي	تَرْمِ	َتَرْمِيَنَّ	ْتَرْمِيَن	–
Dual
2nd	masculine & feminine	ramay-tumā	ta-rmiy-āni	ta-rmiy-ā	ta-rmiy-ā	ta-rmiy-ānni	–	i-rmiy-ā
		رَمَيْتُمَا	تَرْمِيَانِ	تَرْمِيَا	تَرْمِيَا	تَرْمِيَانِّ	–	اِرْمِيَا
3rd	masculine	ramay-ā	ya-rmiy-āni	ya-rmiy-ā	ya-rmiy-ā	ya-rmiy-ānni	–	–
		رَمَيَا	يَرْمِيَانِ	يَرْمِيَا	يَرْمِيَا	يَرْمِيَانِّ	–	–
	feminine	ram-atā	ta-rmiy-āni	ta-rmiy-ā	ta-rmiy-ā	ta-rmiy-ānni	–	–
		رَمَتَا	تَرْمِيَانِ	تَرْمِيَا	تَرْمِيَا	تَرْمِيَانِّ	–	–
Plural
1st		ramay-nā	na-rmī	na-rmiy-a	na-rmi	na-rmiy-anna	na-rmiy-an	–
		رَمَيْنَا	نَرْمِي	َنَرْمِي	نَرْمِ	َنَرْمِيَنَّ	ْنَرْمِيَن	–
2nd	masculine	ramay-tum	ta-rm-ūna	ta-rm-ū	ta-rm-ū	ta-rm-unna	ta-rm-un	i-rm-ū
		رَمَيْتُمْ	تَرْمُونَ	تَرْمُوا	تَرْمُوا	َتَرْمُنَّ	ْتَرْمُن	اِرْمُوا
	feminine	ramay-tunna	ta-rmī-na	ta-rmī-na	ta-rmī-na	ta-rmī-nānni	–	i-rmī-na
		رَمَيْتُنَّ	تَرْمِينَ	تَرْمِينَ	تَرْمِينَ	تَرْمِينَانِّ	–	اِرْمِينَ
3rd	masculine	ram-aw	ya-rm-ūna	ya-rm-ū	ya-rm-ū	ya-rm-unna	ya-rm-un	–
		رَمَوْا	يَرْمُونَ	يَرْمُوا	يَرْمُوا	َيَرْمُنَّ	ْيَرْمُن	–
	feminine	ramay-na	ya-rmī-na	ya-rmī-na	ya-rmī-na	ya-rmī-nānni	–	–
		رَمَيْنَ	يَرْمِينَ	يَرْمِينَ	يَرْمِينَ	يَرْمِينَانِّ	–	–

Two stems each

Each of the two main stems (past and non-past) comes in two variants, a full and a shortened. For the past stem, the full is ramay-, shortened to ram- in much of the third person (i.e. before vowels, in most cases). For the non-past stem, the full is rmiy-, shortened to rm- before -ū -ī. The full non-past stem rmiy- appears as rmī- when not before a vowel; this is an automatic alternation in Classical Arabic. The places where the shortened stems occur are indicated by silver (past), gold (non-past).

Irregular endings

The endings are actually mostly regular. But some endings are irregular, in boldface:

• Some of the third-person past endings are irregular, in particular those in ram-ā 'he threw', ram-aw 'they (masc.) threw'. These simply have to be memorized.
• Two kinds of non-past endings are irregular, both in the "suffixless" parts of the paradigm (largely referring to singular masculine or singular combined-gender). In the indicative, the full stem -rmī actually appears normally; what is irregular is the lack of the -u normally marking the indicative. In the jussive, on the other hand, the stem actually assumes a unique shortened form -rmi, with a short vowel that is not represented by a letter in the Arabic.

faʻā (yafʻū)

The following shows a paradigm of a typical Form I defective (third-weak) verb daʻā (yadʻū) 'to call', parallel to verbs of the faʻala (yafʻulu) type. Verbs of this sort are entirely parallel to verbs of the faʻā (yafʻī) type, although the exact forms can still be tricky. See notes following the table for explanation.

Paradigm of a defective (third-weak) w Arabic verb, daʻā (yadʻū) 'to call'

		Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Singular
1st		daʻaw-tu	a-dʻū	a-dʻuw-a	a-dʻu	a-dʻuw-anna	a-dʻuw-an	–
		دَعَوْتُ	أَدْعُو	َأَدْعُو	أَدْعُ	َأَدْعُوَنَّ	ْأَدْعُوَن	–
2nd	masculine	daʻaw-ta	ta-dʻū	ta-dʻuw-a	ta-dʻu	ta-dʻuw-anna	ta-dʻuw-an	u-dʻu
		دَعَوْتَ	تَدْعُو	َتَدْعُو	تَدْعُ	َتَدْعُوَنَّ	ْتَدْعُوَن	اُدْعُ
	feminine	daʻaw-ti	ta-dʻ-īna	ta-dʻ-ī	ta-dʻ-ī	ta-dʻ-inna	ta-dʻ-in	u-dʻ-ī
		دَعَوْتِ	تَدْعِينَ	تَدْعِي	تَدْعِي	َتَدْعِنَّ	ْتَدْعِن	اُدْعِي
3rd	masculine	daʻ-ā	ya-dʻū	ya-dʻuw-a	ya-dʻu	ya-dʻuw-anna	ya-dʻuw-an	–
		دَعَا	يَدْعُو	َيَدْعُو	يَدْعُ	َيَدْعُوَنَّ	ْيَدْعُوَن	–
	feminine	daʻ-at	ta-dʻū	ta-dʻuw-a	ta-dʻu	ta-dʻuw-anna	ta-dʻuw-an	–
		دَعَتْ	تَدْعُو	َتَدْعُو	تَدْعُ	َتَدْعُوَنَّ	ْتَدْعُوَن	–
Dual
2nd	masculine & feminine	daʻaw-tumā	ta-dʻuw-āni	ta-dʻuw-ā	ta-dʻuw-ā	ta-dʻuw-ānni	–	u-dʻuw-ā
		دَعَوْتُمَا	تَدْعُوَانِ	تَدْعُوَا	تَدْعُوَا	تَدْعُوَانِّ	–	اُدْعُوَا
3rd	masculine	daʻaw-ā	ya-dʻuw-āni	ya-dʻuw-ā	ya-dʻuw-ā	ya-dʻuw-ānni	–	–
		دَعَوَا	يَدْعُوَانِ	يَدْعُوَا	يَدْعُوَا	يَدْعُوَانِّ	–	–
	feminine	daʻ-atā	ta-dʻuw-āni	ta-dʻuw-ā	ta-dʻuw-ā	ta-dʻuw-ānni	–	–
		دَعَتَا	تَدْعُوَانِ	تَدْعُوَا	تَدْعُوَا	تَدْعُوَانِّ	–	–
Plural
1st		daʻaw-nā	na-dʻū	na-dʻuw-a	na-dʻu	na-dʻuw-anna	na-dʻuw-an	–
		دَعَوْنَا	نَدْعُو	َنَدْعُو	نَدْعُ	َنَدْعُوَنَّ	ْنَدْعُوَن	–
2nd	masculine	daʻaw-tum	ta-dʻ-ūna	ta-dʻ-ū	ta-dʻ-ū	ta-dʻ-unna	ta-dʻ-un	u-dʻ-ū
		دَعَوْتُمْ	تَدْعُونَ	تَدْعُوا	تَدْعُوا	َتَدْعُنَّ	ْتَدْعُن	اُدْعُوا
	feminine	daʻaw-tunna	ta-dʻū-na	ta-dʻū-na	ta-dʻū-na	ta-dʻū-nānni	–	u-dʻū-na
		دَعَوْتُنَّ	تَدْعُونَ	تَدْعُونَ	تَدْعُونَ	تَدْعُونَانِّ	–	اُدْعُونَ
3rd	masculine	daʻ-aw	ya-dʻ-ūna	ya-dʻ-ū	ya-dʻ-ū	ya-dʻ-unna	ya-dʻ-un	–
		دَعَوْا	يَدْعُونَ	يَدْعُوا	يَدْعُوا	َيَدْعُنَّ	ْيَدْعُن	–
	feminine	daʻaw-na	ya-dʻū-na	ya-dʻū-na	ya-dʻū-na	ya-dʻū-nānni	–	–
		دَعَوْنَ	يَدْعُونَ	يَدْعُونَ	يَدْعُونَ	يَدْعُونَانِّ	–	–

Verbs of this sort are work nearly identically to verbs of the faʻā (yafʻī) type. There are the same irregular endings in the same places, and again two stems in each of the past and non-past tenses, with the same stems used in the same places:

• In the past, the full stem is daʻaw-, shortened to daʻ-.
• In the non-past, the full stem is dʻuw-, rendered as dʻū- when not before a vowel and shortened to dʻ- before -ū -ī.

The Arabic spelling has the following rules:

• In the third person masculine singular past, regular alif appears instead of alif maqṣūrah: hence دَعَا not *دَعَى.
• The otiose final alif appears only after the final wāw of the plural, not elsewhere: hence تَدْعُو 'you (masc. sg.) call (indic.)' but تَدْعُوا 'you (masc. pl.) call (subj.)', even though they are both pronounced tadʻū.

faʻiya (yafʻā)

The following shows a paradigm of a typical Form I defective (third-weak) verb nasiya (yansā) 'to forget', parallel to verbs of the faʻila (yafʻalu) type. These verbs differ in a number of significant respects from either of the above types.

Paradigm of a defective (third-weak) a Arabic verb, nasiya (yansā) 'to forget'

		Past	Present Indicative	Subjunctive	Jussive	Long Energetic	Short Energetic	Imperative
Singular
1st		nasī-tu	a-nsā	a-nsā	a-nsa	a-nsay-anna	a-nsay-an	–
		نَسِيتُ	أَنْسَى	أَنْسَى	أَنْسَ	َأَنْسَيَنَّ	ْأَنْسَيَن	–
2nd	masculine	nasī-ta	ta-nsā	ta-nsā	ta-nsa	ta-nsay-anna	ta-nsay-an	i-nsa
		نَسِيتَ	تَنْسَى	تَنْسَى	تَنْسَ	َتَنْسَيَنَّ	ْتَنْسَيَن	اِنْسَ
	feminine	nasī-ti	ta-nsa-yna	ta-nsa-y	ta-nsa-y	ta-nsa-yinna	ta-nsa-yin	i-nsa-y
		نَسِيتِ	تَنْسَيْنَ	تَنْسَيْ	تَنْسَيْ	َتَنْسَيِنَّ	ْتَنْسَيِن	اِنْسَيْ
3rd	masculine	nasiy-a	ya-nsā	ya-nsā	ya-nsa	ya-nsay-anna	ya-nsay-an	–
		نَسِيَ	يَنْسَى	يَنْسَى	يَنْسَ	َيَنْسَيَنَّ	ْيَنْسَيَن	–
	feminine	nasiy-at	ta-nsā	ta-nsā	ta-nsa	ta-nsay-anna	ta-nsay-an	–
		نَسِيَتْ	تَنْسَى	تَنْسَى	تَنْسَ	َتَنْسَيَنَّ	ْتَنْسَيَن	–
Dual
2nd	masculine & feminine	nasī-tumā	ta-nsay-āni	ta-nsay-ā	ta-nsay-ā	ta-nsay-ānni	–	i-nsay-ā
		نَسِيتُمَا	تَنْسَيَانِ	تَنْسَيَا	تَنْسَيَا	تَنْسَيَانِّ	–	اِنْسَيَا
3rd	masculine	nasiy-ā	ya-nsay-āni	ya-nsay-ā	ya-nsay-ā	ya-nsay-ānni	–	–
		نَسِيَا	يَنْسَيَانِ	يَنْسَيَا	يَنْسَيَا	يَنْسَيَانِّ	–	–
	feminine	nasiy-atā	ta-nsay-āni	ta-nsay-ā	ta-nsay-ā	ta-nsay-ānni	–	–
		نَسِيَتَا	تَنْسَيَانِ	تَنْسَيَا	تَنْسَيَا	تَنْسَيَانِّ	–	–
Plural
1st		nasī-nā	na-nsā	na-nsā	na-nsa	na-nsay-anna	na-nsay-an	–
		نَسِينَا	نَنْسَى	نَنْسَى	نَنْسَ	َنَنْسَيَنَّ	ْنَنْسَيَن	–
2nd	masculine	nasī-tum	ta-nsa-wna	ta-nsa-w	ta-nsa-w	ta-nsa-wunna	ta-nsa-wun	i-nsa-w
		نَسِيتُمْ	تَنْسَوْنَ	تَنْسَوْا	تَنْسَوْا	َتَنْسَوُنَّ	ْتَنْسَوُن	اِنْسَوْا
	feminine	nasī-tunna	ta-nsay-na	ta-nsay-na	ta-nsay-na	ta-nsay-nānni	–	i-nsay-na
		نَسِيتُنَّ	تَنْسَيْنَ	تَنْسَيْنَ	تَنْسَيْنَ	تَنْسَيْنَانِّ	–	اِنْسَيْنَ
3rd	masculine	nas-ū	ya-nsa-wna	ya-nsa-w	ya-nsa-w	ya-nsa-wunna	ya-nsa-wun	–
		نَسُوا	يَنْسَوْنَ	يَنْسَوْا	يَنْسَوْا	َيَنْسَوُنَّ	ْيَنْسَوُن	–
	feminine	nasī-na	ya-nsay-na	ya-nsay-na	ya-nsay-na	ya-nsay-nānni	–	–
		نَسِينَ	يَنْسَيْنَ	يَنْسَيْنَ	يَنْسَيْنَ	يَنْسَيْنَانِّ	–	–

Multiple stems

This variant is somewhat different from the variants with -ī or -ū in the non-past. As with other third-weak verbs, there are multiple stems in each of the past and non-past, a full stem composed following the normal rules and one or more shortened stems.

• In this case, only one form in the past uses a shortened stem: nas-ū 'they (masc.) forgot'. All other forms are constructed regularly, using the full stem nasiy- or its automatic pre-consonant variant nasī-.
• In the non-past, however, there are at least three different stems:

1. The full stem -nsay- occurs before -a/ā- or -n-, that is before dual endings, feminine plural endings and energetic endings corresponding to forms that are endingless in the jussive.
2. The modified stem -nsā occurs in "endingless" forms (i.e. masculine or common-gender singular, plus 1st plural). As usual with third-weak verbs, it is shortened to -nsa in the jussive. These forms are marked with red.
3. Before endings normally beginning with -i/ī- or -u/ū-, the stem and endings combine together into a shortened form: e.g. expected *ta-nsay-īna 'you (fem. sg.) forget', *ta-nsay-ūna 'you (masc. pl.) forget' instead become ta-nsayna, ta-nsawna respectively. The table above chooses to segment them as ta-nsa-yna, ta-nsa-wna, suggesting that a shortened stem -nsa- combines with irregular (compressed) endings -yna < *-īna, -wna < *-ūna. Similarly subjunctive/jussive ta-nsaw < *ta-nsay-ū; but note energetic ta-nsawunna < *ta-nsay-unna, where the original *-yu- has assimilated to -wu-. Consistent with the above analysis, we analyze this form as ta-nsa-wunna, with an irregular energetic ending -wunna where a glide consonant has developed after the previous vowel. However, since all moods in this case have a form containing -nsaw-, an alternative analysis would consider -nsaw and -nsay as stems. These forms are marked with gold.

Irregular endings

The endings are actually mostly regular. But some endings are irregular in the non-past, in boldface:

• The non-past endings in the "suffixless" parts of the paradigm (largely referring to singular masculine or singular combined-gender). In the indicative and subjunctive, the modified stem -nsā appears, and is shortened to -nsa in the jussive. In the forms actually appears normally; what is irregular is the lack of the -u normally marking the indicative. In the jussive, on the other hand, the stem actually assumes a unique shortened form -nsa, with a short vowel that is not represented by a letter in the Arabic script.
• In the forms that would normally have suffixes -i/ī- or -u/ū-, the stem and suffix combine to produce -nsay-, -nsaw-. These are analyzed here as consisting of a shortened stem form -nsa- plus irregular (shortened or assimilated) endings.

Formation of derived stems ("forms")

Arabic verb morphology includes augmentations of the root, also known as forms, an example of the derived stems found among the Semitic languages. For a typical verb based on a triliteral root (i.e. a root formed using three root consonants), the basic form is termed Form I, while the augmented forms are known as Form II, Form III, etc. The forms in normal use are Form I through Form X; Forms XI through XV exist but are rare and obsolescent. Forms IX and XI are used only with adjectival roots referring to colors and physical defects (e.g. "red", "blue", "blind", "deaf", etc.), and are stative verbs having the meaning of "be X" or "become X" (e.g. Form IX iḥmarra 'be red, become red, blush', Form XI iḥmārra with the same meaning). Although the structure that a given root assumes in a particular augmentation is predictable, its meaning is not (although many augmentations have one or more "usual" or prototypical meanings associated with them), and not all augmentations exist for any given root. As a result, these augmentations are part of the system of derivational morphology, not part of the inflectional system.

The construction of a given augmentation is normally indicated using the dummy root f–ʻ–l (ف–ع–ل), based on the verb faʻala 'to do'. Because Arabic has no direct equivalent to the infinitive form of Western languages, the third-person masculine singular past tense is normally used as the dictionary form of a given verb, i.e. the form by which a verb is identified in a dictionary or grammatical discussion. Hence, the word faʻala above actually has the meaning of 'he did', but is translated as 'to do' when used as a dictionary form.

Verbs based on quadriliteral roots (roots with four consonants) also exist. There are four augmentations for such verbs, known as Forms Iq, IIq, IIIq and IVq. These have forms similar to Forms II, V, VII and IX respectively of triliteral verbs. Forms IIIq and IVq are fairly rare. The construction of such verbs is typically given using the dummy verb faʻlala. However, the choice of this particular verb is somewhat non-ideal in that the third and fourth consonants of an actual verb are typically not the same, despite the same consonant used for both; this is a particular problem e.g. for Form IVq. The verb tables below use the dummy verb faʻlaqa instead.

Some grammars, especially of colloquial spoken varieties rather than of Classical Arabic, use other dummy roots. For example, A Short Reference Grammar of Iraqi Arabic (Wallace M. Erwin) uses FaMaLa and FaSTaLa for three and four-character roots, respectively (standing for "First Middle Last" and "First Second Third Last"). Commonly the dummy consonants are given in capital letters.

The system of identifying verb augmentations by Roman numerals is an invention by Western scholars. Traditionally, Arabic grammarians did not number the augmentations at all, instead identifying them by the corresponding dictionary form. For example, Form V would be called "the tafaʻʻala form".

Verbs						Derived nouns			Typical meanings, notes	Examples
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	faʻala	yafʻulu	ufʻul	fuʻila	yufʻalu	fāʻil	mafʻūl	faʻl, fuʻūl, fiʻl, fuʻl(ah), faʻāl(ah), fiʻāl(ah), etc.	basic verb form	kataba (yaktubu) 'write"; dakhala (yadkhulu) 'enter'; darasa (yadrusu) 'study"; qatala (yaqtulu) "kill"
	faʻala	yafʻilu	ifʻil							ḥamala (yaḥmilu) 'carry'; qadara (yaqdiru) 'be able'; ʻarafa (yaʻrifu) 'know'; jalasa (yajlisu) 'sit'
	faʻala	yafʻalu	ifʻal						usually with a guttural consonant (ʼ ʻ h ḥ) in second or third position	qaṭaʻa (yaqṭaʻu) 'cut'; qaraʼa (yaqraʼu) "read"; ẓahara (yaẓharu) 'seem'; baḥatha (yabḥathu) 'search'
	faʻila	yafʻalu	ifʻal						often stative verbs (temporary conditions)	fahima (yafhamu) 'understand'; rakiba (yarkabu) 'ride'; shariba (yashrabu) 'drink'; labisa (yalbasu) 'wear'
	faʻila	yafʻilu	ifʻil						often stative verbs (temporary conditions); rare except with initial w consonant (which disappears in non-past)	ḥasiba (yaḥsibu) 'estimate'; wathiqa (yathiqu) 'trust'
	faʻula	yafʻulu	ufʻul						only with stative verbs (permanent conditions)	kabura (yakburu) 'grow big, grow old'; kathura (yakthuru) 'be many, be numerous'; baʻuda (yabʻudu) 'be distant (from)'; karuma (yakrumu) 'be/become noble'
II	faʻʻala	yufaʻʻilu	faʻʻil	fuʻʻila	yufaʻʻalu	mufaʻʻil	mufaʻʻal	tafʻīl	causative and intensive; denominative; transitive of form 1.	kattaba 'make (someone) write (something)'; dakhkhala 'bring in (someone/something)'; darrasa 'teach'; qattala 'massacre'; ḥammala 'burden, impose'; ʻarrafa 'announce, inform'; qaṭṭaʻa "cut into pieces"
III	fāʻala	yufāʻilu	fāʻil	fūʻila	yufāʻalu	mufāʻil	mufāʻal	mufāʻalah, fiʻāl	the verbs in this form need an indirect object which is often "with" and sometimes "against".	kātaba 'write to, correspond with (someone)'; dākhala 'befall (someone)'; dārasa 'study with (someone)'; qātala 'fight'; jālasa 'sit with (someone), keep (someone) company'; qāṭaʻa 'disassociate (from), interrupt, cut off (someone)'
IV	afʻala	yufʻilu	afʻil	ufʻila	yufʻalu	mufʻil	mufʻal	ifʻāl	usually transitive and causative of form 1 (this form has not intensive meaning).	aktaba 'dictate'; adkhala 'bring in (someone), bring about (something)'; aqdara 'enable'; ajlasa 'seat'; aqṭaʻa 'make (someone) cut off (something), part company with, bestow as a fief'
V	tafaʻʻala	yatafaʻʻalu	tafaʻʻal	tufuʻʻila	yutafaʻʻalu	mutafaʻʻil	mutafaʻʻal	tafaʻʻul	usually reflexive of Form II.	tadakhkhala 'interfere, disturb'; tadarrasa 'learn'; taḥammala 'endure, undergo'; taʻarrafa 'become acquainted (with someone), meet'; taqaṭṭaʻa 'be cut off, be disrupted, be intermittent'
VI	tafāʻala	yatafāʻalu	tafāʻal	tufūʻila	yutafāʻalu	mutafāʻil	mutafāʻal	tafāʻul	reciprocal of Form III; and even "pretend to X"	takātaba 'correspond with each other'; tadākhala 'meddle, butt in'; tadārasa 'study carefully with each other'; taqātala 'fight with one another'; taḥāmala 'maltreat, be biased (against)'; taʻarrafa 'become mutually acquainted, come to know (something)'; taqāṭaʻa 'part company, break off mutual relations, intersect (of roads)'
VII	infaʻala	yanfaʻilu	infaʻil	(unfuʻila)	(yunfaʻalu)	munfaʻil	munfaʻal	infiʻāl	anticausative verb of Form I;	inkataba 'subscribe'; inqaṭaʻa 'be cut off, cease, suspend'
VIII	iftaʻala	yaftaʻilu	iftaʻil	uftuʻila	yuftaʻalu	muftaʻil	muftaʻal	iftiʻāl	reflexive of Form I; often some unpredictable variation in meaning	iktataba 'copy (something), be recorded'; iqtatala 'fight (with)'; iḥtamala 'carry away, endure, allow'; iqtadara 'be able'; iʻtarafa 'confess, recognize'; ; iqtaṭaʻa 'take a part (of something), tear out/off, deduct'
IX	ifʻalla	yafʻallu	ifʻalil	(ufʻulla)	(yufʻallu)	mufʻall	n/a	ifʻilāl	stative verb ("be X", "become X"), specially for colors (e.g. "red", "blue") and physical defects.	iḥmarra 'turn red, blush'; iswadda 'be/become black'; iṣfarra 'turn yellow, become pale'; iḥwalla 'be cross-eyed, squint'
X	istafʻala	yastafʻilu	istafʻil	ustufʻila	yustafʻalu	mustafʻil	mustafʻal	istifʻāl	"ask to X"; "want to X"; "consider (someone) to be X"; causative, and sometimes autocausative verb; often some unpredictable variation in meaning	istaktaba 'ask (someone) to write (something)'; istaqtala 'risk one's life'; istaqdara 'ask (God) for strength or ability'; istaʻrafa 'discern, recognize'; istaqṭaʻa 'request as a fief'
XI	ifʻālla	yafʻāllu	ifʻālil	n/a		mufʻāll	n/a	ifʻīlāl	rare except in poetry; same meaning as Form IX	iḥmārra "turn red, blush"; iṣhābba 'be/become reddish-brown'; ilhājja 'curdle'
XII	ifʻawʻala	yafʻawʻilu	ifʻawʻil	ufʻūʻila	yufʻawʻalu	mufʻawʻil	mufʻawʻal	ifʻīʻāl	very rare, with specialized meanings; often stative	iḥdawdaba 'be convex, be hunchbacked'; ighdawdana 'grow long and luxuriantly (of hair)'; iḥlawlaka 'be pitch-black'; ikhshawshana 'be rough/crude, lead a rough life'
XIII	ifʻawwala	yafʻawwilu	ifʻawwil	ufʻuwwila	yufʻawwalu	mufʻawwil	mufʻawwal	ifʻiwwāl		ijlawwadha 'gallop'; iʻlawwaṭa 'hang on the neck of (a camel)'
XIV	ifʻanlala	yafʻanlilu	ifʻanlil	ufʻunlila	yufʻanlalu	mufʻanlil	mufʻanlal	ifʻinlāl		iqʻansasa 'have a protruding chest and hollow back, be pigeon-breasted'; iqʻandada 'reside'; isḥankaka 'become very dark'
XV	ifʻanlā	yafʻanlā	ifʻanla	ufʻunliya	yufʻanlā	mufʻanlin	mufʻanlan	ifʻinlāʼ		iḥranbā 'become very furious'; ighrandā 'curse and hit (someone)'
Iq	faʻlaqa	yufaʻliqu	faʻliq	fuʻliqa	yufaʻlaqu	mufaʻliq	mufaʻlaq	faʻlaqat, occ. faʻlāq, fiʻlāq	basic form, often transitive or denominative; similar to Form II, but verbal noun is different; reduplicated roots of the form faʻfaʻa are common, sometimes faʻfala is also seen	daḥraja 'roll (something)'; tarjama 'translate, interpret'; handasa 'sketch, make a plan'; bayṭara 'practice veterinary surgery' (< 'veter(inary)'); zalzala 'shake (something), frighten'; waswasa 'whisper'; gharghara "gargle"
IIq	tafaʻlaqa	yatafaʻlaqu	tafaʻlaq	tufuʻliqa	yutafaʻlaqu	mutafaʻliq	mutafaʻlaq	tafaʻluq	reflexive of Form Iq; frequentative intransitive denominative; similar to Form V	tadaḥraja 'roll' (intrans.)'; tazalzala 'shake (intrans.), tremble'; tafalsafa 'philosophize' (< faylasūf- 'philosopher'); tamadhhaba 'follow a sect' (< madhhab- 'sect' < dhahaba 'go'); taqahqara 'be driven back'
IIIq	ifʻanlaqa	yafʻanliqu	ifʻanliq	ufʻunliqa	yufʻanlaqu	mufʻanliq	mufʻanlaq	ifʻinlāq	rare	ikhranṭama 'be proud' (cf. al-Kharṭūm- 'Khartoum')
IVq	ifʻalaqqa	yafʻaliqqu	ifʻalqiq	ufʻuliqqa	yufʻalaqqu	mufʻaliqq	mufʻalaqq	ifʻilqāq	usually intransitive; somewhat rare	iṭmaʼanna 'be tranquil, calm'; iḍmaḥalla 'fade away, dwindle'; iqshaʻarra 'shudder with horror'

Each form can have either active or passive forms in the past and non-past tenses, so reflexives are different from passives.

Note that the present passive of forms I and IV are the same. Otherwise there is no confusion.

Sound verbs

Sound verbs are those verbs with no associated irregularities in their constructions. Verbs with irregularities are known as weak verbs; generally, this occurs either with (1) verbs based on roots where one or more of the consonants (or radicals) is w (و), y (ي) or the glottal stop ʼ (ﺀ) (also known by the Arabic names of the corresponding letters, which are wāw, yāʼ and hamzah, respectively); or (2) verbs where the second and third root consonants are the same.

Some verbs that would be classified as "weak" according to the consonants of the verb root are nevertheless conjugated as a strong verb. This happens, for example:

• Largely, to all verbs whose only weakness is a hamzah radical; the irregularity is in the Arabic spelling but not the pronunciation, except in a few minor cases.
• Largely, to all verbs whose only weakness is a y in the first radical (the "assimilated" type).
• To all verbs conjugated in Forms II, III, V, VI whose only weakness is a w or y in the first or second radicals (or both).

Form VIII assimilations

Form VIII has a -t- that is infixed into the root, directly after the first root consonant. This -t- assimilates to certain coronal consonants occurring as the first root consonant. In particular, with roots whose first consonant is d z th dh ṣ ṭ ḍ ẓ, the combination of root and infix t appears as dd zd thth dhdh ṣṭ ṭṭ ḍṭ ẓẓ. That is, the t assimilates the emphasis of the emphatic consonants ṣ ṭ ḍ ẓ and the voicing of d z, and assimilates entirely to the interdental consonants th dh ẓ. The consonant cluster ḍṭ, as in iḍṭarra 'compel, force', is unexpected given modern pronunciation, having a voiced stop next to a voiceless one; this reflects the fact that ṭ was formerly pronounced voiced, and ḍ was pronounced as the emphatic equivalent not of d but of an unusual lateral sound. (ḍ was possibly an emphatic voiced alveolar lateral fricative /ɮˤ/ or a similar affricated sound /dɮˤ/ or /dˡˤ/; see the article on the letter ḍād.)

Defective (third-weak) verbs

Other than for Form I active, there is only one possible form for each verb, regardless of whether the third root consonant is w or y. All of the derived third-weak verbs have the same active-voice endings as faʻā (yafʻī) verbs except for Forms V and VI, which have past-tense endings like faʻā (yafʻī) verbs but non-past endings like faʻiya (yafʻā) verbs. The passive-voice endings of all third-weak verbs (whether Form I or derived) are the same as for the faʻiya (yafʻā) verbs. The verbal nouns have various irregularities: feminine in Form II, -in declension in Form V and VI, glottal stop in place of root w/y in Forms VII–X.

The active and passive participles of derived defective verbs consistently are of the -in and -an declensions, respectively.

Defective Form IX verbs are extremely rare. Heywood and Nahmad list one such verb, iʻmāya 'be/become blind', which does not follow the expected form *iʻmayya. They also list a similarly rare Form XI verb iʻmāyya 'be/become blind' — this time with the expected form.

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	faʻā	yafʻī	ifʻi	fuʻiya	yufʻā	fāʻin	mafʻiyy	faʻy, faʻw, faʻan, fiʻan, faʻāʼ, fāʻiyah, fiʻāyah, faʻāwah, mafʻāh, mafʻiyah, fuʻyah, fuʻwah, fuʻuww, fuʻwān etc.
	faʻā	yafʻū	ufʻu				mafʻuww
	faʻiya	yafʻā	ifʻa				mafʻiyy
II	faʻʻā	yufaʻʻī	faʻʻi	fuʻʻiya	yufaʻʻā	mufaʻʻin	mufaʻʻan	tafʻiyah
III	fāʻā	yufāʻī	fāʻi	fūʻiya	yufāʻā	mufāʻin	mufāʻan	mufāʻāh, fiʻāʼ
IV	afʻā	yufʻī	afʻi	ufʻiya	yufʻā	mufʻin	mufʻan	ifʻāʼ
V	tafaʻʻā	yatafaʻʻā	tafaʻʻa	tufuʻʻiya	yutafaʻʻā	mutafaʻʻin	mutafaʻʻan	tafaʻʻin
VI	tafāʻā	yatafāʻā	tafāʻa	tufūʻiya	yutafāʻā	mutafāʻin	mutafāʻan	tafāʻin
VII	infaʻā	yanfaʻī	infaʻi	(unfuʻī)	(yunfaʻā)	munfaʻin	munfaʻan	infiʻāʼ
VIII	iftaʻā	yaftaʻī	iftaʻi	uftuʻiya	yuftaʻā	muftaʻin	muftaʻan	iftiʻāʼ
IX	ifʻāya (ifʻayaytu?)	yafʻāyu (yafʻayna?)	ifʻay?	—	—	mufʻāy	—	ifʻiyāʼ
X	istafʻā	yastafʻī	istafʻi	ustufʻiya	yustafʻā	mustafʻin	mustafʻan	istifʻāʼ

Hollow (second-weak) verbs

Only the forms with irregularities are shown. The missing forms are entirely regular, with w or y appearing as the second radical, depending on the root. There are unexpected feminine forms of the verbal nouns of Form IV, X.

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	fāla (filtu)	yafīlu	fil	fuwila	yufālu	fāʼil	mafīl	usually fawl, fayl; also fūl, fawāl, fiyāl(ah), fiwāl, fuwāl, mafāl(ah), mafīl etc.
	fāla (fultu)	yafūlu	ful				mafūl
	fāla (filtu)	yafālu	fal				mafīl
	fāla (fultu)	yafālu	fal				mafūl
IV	afāla (ʼafaltu)	yufīlu	afil	ufīla	yufālu	mufīl	mufāl	ifālah
VII	infāla (infaltu)	yanfālu	infal	n/a		munfāl	munfāl	infiyāl
VIII	iftāla (iftaltu)	yaftālu	iftal	uftīla	yuftālu	muftāl	muftāl	iftiyāl
X	istafāla	yastafīlu	istafil	ustufīla	yustafālu	mustafīl	mustafāl	istifālah

Assimilated (first-weak) verbs

When the first radical is w, it drops out in the Form I non-past. Most of the derived forms are regular, except that the sequences uw iw are assimilated to ū ī, and the sequence wt in Form VIII is assimilated to tt throughout the paradigm. The following table only shows forms with irregularities in them.

The initial w also drops out in the common Form I verbal noun ʻilah (e.g. ṣilah 'arrival, link' from waṣalah 'arrive').

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	waʻala	yaʻulu	ʻul	wuʻila	yūʻalu	wāʻil-	mawʻūd-	waʻl, wuʻūl, ʻilah etc.
	waʻala	yaʻilu	ʻil
	waʻala	yaʻalu	ʻal
	waʻila	yaʻalu	ʻal
	waʻila	yaʻilu	ʻil
	waʻula	yaʻulu	ʻul
IV	ʼawʻala	yūʻilu	ʼawʻil	ʼūʻila	yūʻalu	mūʻil-	mūʻal-	ʼīʻāl-
VIII	ittaʻala	yattaʻilu	ittaʻal	uttuʻila	yuttaʻalu	muttaʻil-	muttaʻal-	ittiʻāl-
X	istawʻala	yastawʻilu	istawʻil	ustūʻila	yustawʻalu	mustawʻil-	mustawʻal-	istīʻāl-

When the first radical is y, the forms are largely regular. The following table only shows forms that have some irregularities in them, indicated in boldface.

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	yaʻala	yayʻulu	ūʻul	yuʻila	yūʻalu	yāʻil-	mayʻūd-	yaʻl- etc.
	yaʻala	yayʻilu	īʻil
	waʻala	yayʻalu	īʻal
	waʻila	yayʻalu	īʻal
	waʻila	yayʻilu	īʻil
	waʻula	yayʻulu	ūʻul
IV	ʼayʻala	yūʻilu	ʼayʻil	ʼūʻila	yūʻalu	mūʻil-	mūʻal-	ʼīʻāl-
VIII	ittaʻala	yattaʻilu	ittaʻal	uttuʻila	yuttaʻalu	muttaʻil-	muttaʻal-	ittiʻāl-
X	istayʻala	yastayʻilu	istayʻil	ustūʻila	yustayʻalu	mustayʻil-	mustayʻal-	istīʻāl-

Doubled verbs

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	falla (falaltu)	yafullu	fulla, fulli, uflul	fulla	yufallu	fāll-	maflūl-	fall- etc.
	falla (falaltu)	yafillu	filla, filli, iflil
	falla (falaltu)	yafallu	falla, falli, iflal
	falla (faliltu)	yafallu	falla, falli, iflal
III	fālla	yufāllu	fālla, fālli, fālil	fūlla	yufāllu	mufāll-	mufāll-	mufāllat-, filāl-
IV	afalla	yufillu	afilla, afilli, aflil	ufilla	yufallu	mufill-	mufall-	iflāl-
VI	tafālla	yatafāllu	tafālil	tufūlla	yutafāllu	mutafāll-	mutafāll-	tafāll-
VII	infalla	yanfallu	infalla, infalli, infalil	n/a		munfall-	munfall-	infilāl-
VIII	iftalla	yaftallu	iftalla, iftalli, iftalil	uftulla	yuftallu	muftall-	muftall-	iftilāl-
X	istafalla	yastafillu	istafilla, istafilli, istaflil	ustufilla	yustafallu	mustafill-	mustafall-	istiflāl-

Hamzated verbs

The largest problem with so-called "hamzated" verbs (those with a glottal stop ʼ or "hamzah" as any of the root consonants) is the complicated way of writing such verbs in the Arabic script (see the article on hamzah for the rules regarding this). In pronunciation, these verbs are in fact almost entirely regular.

The only irregularity occurs in verbs with a hamzah as the first radical. A phonological rule in Classical Arabic disallows the occurrence of two hamzahs in a row separated by a short vowel, assimilating the second to the preceding vowel (hence ʼaʼ ʼiʼ ʼuʼ become ʼā ʼī ʼū). This affects the following forms:

• The first-person singular of the non-past of Forms I, IV and VIII.
• The entire past and imperative of Form IV.

In addition, any place where a hamzat al-waṣl (elidable hamzah) occurs will optionally undergo this transformation. This affects the following forms:

• The entire imperative of Form I.
• The entire past and imperative of Form VIII, as well as the verbal noun of Form VIII.

There are the following irregularities:

• The common verbs ʼakala 'eat', ʼakhadha 'take', ʼamara 'command' have irregular, short imperatives kul, khudh, mur.
• Form VIII of the common verb ʼakhadha 'take' is ittakhadha 'take on, assume', with irregular assimilation of the hamzah.
• The common verb saʼala yasʼalu 'ask' has an alternative non-past yasalu with missing hamzah.

Verbs						Derived nouns
	Active voice			Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Imperative (2nd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Sg. masc. nom.
I	ʼaʻala	yaʼʻulu (ʼāʻulu)	uʼʻul, ūʻul	ʼuʻila	yuʼʻalu (ʼūʻalu)	ʼāʻil	maʼʻūl-	ʼaʻl- etc.
etc.
IV	ʼāʻala	yuʼʻilu (ʼūʻilu)	ʼāʻil	ʼūʻil	yuʼʻalu (ʼūʻalu)	muʼʻil-	muʼʻal-	ʼīʻāl-
VIII	iʼtaʻala, ītaʻala	yaʼtaʻilu (ʼātaʻilu)	iʼtaʻil, ītaʻil	uʼtuʻila, ūtuʻila	yuʼtaʻala (ʼūtaʻala)	muʼtaʻil-	muʼtaʻal-	iʼtiʻāl-, ītiʻāl-

Doubly weak verbs

Doubly weak verbs have two "weak" radicals; a few verbs are also triply weak. Generally, the above rules for weak verbs apply in combination, as long as they do not conflict. The following are cases where two types of weaknesses apply in combination:

• Verbs with a w in the first radical and a w or y in the third radical. These decline as defective (third-weak) verbs, and also undergo the loss of w in the non-past of Form I, e.g. waqā yaqī 'guard', wafā yafī 'complete, fulfill (a promise)', waliya yalī 'be near, follow'. These verbs have extremely short imperatives qi fi li (feminine qī fī lī, masculine plural qū fū lū, feminine plural iqna ifna ilna), although these are not normally used in Modern Standard Arabic. Similarly, verbs of this sort in Form IV and Form VIII are declined as defective but also have the normal assimilations of w-initial verbs, e.g. Form IV awfā yūfī 'fulfill a vow', Form VIII ittaqā yattaqī 'fear (God)', augmentations of wafā yafī and waqā yaqī, respectively (see above).
• Verbs with a hamzah in the first radical and a w or y in the third radical. These decline as defective (third-weak) verbs, and also undergo the assimilations associated with the initial hamzah, e.g. the common verb ʼatā yaʼtī 'come' (first singular non-past ʼātī 'I come') and the related Form IV verb ʼātā yuʼtī 'bring' (first singular non-past ʼūtī 'I bring').

The following are examples where weaknesses would conflict, and hence one of the "weak" radicals is treated as strong:

• Verbs with a w or y in both the second and third radicals. These are fairly common, e.g. rawā yarwī 'recount, transmit'. These decline as regular defective (third-weak) verbs; the second radical is treated as non-weak.
• Verbs with a w in the first radical and the second and third radicals the same. These verbs do not undergo any assimilations associated with the first radical, e.g. wadda (wadidtu) yawaddu 'to love'.
• Verbs with a hamza in the first radical and the second and third radicals the same. These verbs do not undergo any assimilations associated with the first radical, e.g. ʼajja yaʼujju 'burn', first singular non-past ʼaʼujju 'I burn', despite the two hamzahs in a row.

The following are cases with special irregularities:

• Verbs with a w or y in the second radical and a hamzah in the third radical. These are fairly common, e.g. the extremely common verb jāʼa yajīʼu 'come'. The only irregularity is the Form I active participle, e.g. jāʼin 'coming', which is irregularly declined as a defective (third-weak) participle (presumably to avoid a sequence of two hamzahs in a row, as the expected form would be *jāʼiʼ).
• The extremely common verb raʼā yarā 'see'. The hamzah drops out entirely in the non-past. Similarly in the passive, ruʼiya yurā 'be seen'. The active participle is regular rāʼin and the passive participle is regular marʼīy-. The related Form IV verb arā yūrī 'show' is missing the hamzah throughout. Other augmentations are regular: Form III rāʼā yurāʼī 'dissemble', Form VI tarāʼā yatarāʼā 'look at one another', Form VIII irtaʼā yartaʼī 'think'.
• The common verb ḥayiya yaḥyā 'live', with an alternative past tense ḥayya. Form IV aḥyā yuḥyī 'resuscitate, revive' is regular. Form X istaḥyā yastaḥyī 'spare alive, feel ashamed' also appears as istaḥayya and istaḥā.

Summary of vowels

The vowels for the various forms are summarized in this table:

	Active voice		Passive voice		Active participle	Passive participle	Verbal noun
	Past (3rd sg. masc.)	Present (3rd sg. masc.)	Past (3rd sg. masc.)	Present (3rd sg. masc.)
Before first root consonant (if vowel is present)	a in Forms IV-VI. In Forms VII-XII one has i when the hamzah is not elided.	a except in Forms II-IV, where it is u.	u	u, and a after the t of Forms V and VI	u	u except in Form I, where it is a.	a in Forms II, V, and VI. In Forms VII-XII one has i when the hamzah is not elided.
Just before 2nd root consonant	a, ā, or none	a, ā, or none	u, ū, or none	a, ā, or none	a, ā, or none	a, ā, or none	i, a, ā, or none
Just before third root consonant	a	Form I a, i, or u. a in Forms V, VI, and IX, i in others.	i	a	i except in Form IX, where it is a.	a except in Form I, where it is ū.	ī in Form II, u in Forms V and VI, ā elsewhere
After final root consonant, 3rd person sing. indicative	a	u	a	u	n/a	n/a	n/a

See also Wiktionary's appendix on Arabic verb forms.

Participle

Every verb has a corresponding active participle, and most have passive participles. E.g. muʻallim 'teacher' is the active participle to stem II. of the root ʻ-l-m ('know').

• The active participle to Stem I is fāʻil, and the passive participle is mafʻūl.
• Stems II-X take prefix mu- and nominal endings for both the participles, active and passive. The difference between the two participles is only in the vowel between the last two root letters, which is -i- for active and -a- for passive (e.g. II. active mu-faʻʻil, and passive mu-faʻʻal).

Verbal noun (maṣdar)

In addition to a participle, there is a verbal noun (in Arabic, مَصْدَر maṣdar, pl. مَصَادِر maṣādir, literally meaning 'source'), sometimes called a gerund, which is similar to English gerunds and verb-derived nouns of various sorts (e.g. "running" and "a run" from "to run"; "objection" from "to object"). As shown by the English examples, its meaning refers both to the act of doing something and (by frequent semantic extension) to its result. One of its syntactic functions is as a verbal complement of another verb, and this usage it corresponds to the English gerund or infinitive (He prevented me from running or He began to run).

• verbal noun formation to stem I is irregular.
• the verbal noun to stem II is tafʻīl. For example: taḥḍīr 'preparation' is the verbal noun to stem II. of ḥ-ḍ-r ('to be present').
• stem III often forms its verbal noun with the feminine form of the passive participle, so for sāʻada, 'he helped', produces the verbal noun musāʻadah. There are also some verbal nouns of the form fiʻāl: jāhada, 'he strove', yields jihād 'a struggle' (for a cause or purpose).

Some well-known examples of verbal nouns are fatḥ (see Fatah) (Form I), tanẓīm (Form II), jihād (Form III), islām (Form IV), intifāḍah (feminine of Form VIII verbal noun), and istiqlāl (Form X).

Verbs in colloquial Arabic

The Classical Arabic system of verbs is largely unchanged in the colloquial spoken varieties of Arabic. The same derivational system of augmentations exists, including triliteral Forms I through X and quadriliteral Forms I and II, constructed largely in the same fashion (the rare triliteral Forms XI through XV and quadriliteral Forms III and IV have vanished). The same system of weaknesses (strong, defective/third-weak, hollow/second-weak, assimilated/first-weak, doubled) also exists, again constructed largely in the same fashion. Within a given verb, two stems (past and non-past) still exist along with the same two systems of affixes (suffixing past-tense forms and prefixing/suffixing non-past forms).

The largest changes are within a given paradigm, with a significant reduction in the number of forms. The following is an example of a regular verb paradigm in Egyptian Arabic.

Example of a regular Form I verb in Egyptian Arabic, kátab/yíktib "write"

Tense/Mood		Past	Present Subjunctive	Present Indicative	Future	Imperative
Singular
1st		katáb-t كتبت	á-ktib أكتب	bá-ktib بكتب	ḥá-ktib حكتب
2nd	masculine	katáb-t كتبت	tí-ktib تكتب	bi-tí-ktib بتكتب	ḥa-tí-ktib حتكتب	í-ktib اكتب
	feminine	katáb-ti كتبت	ti-ktíb-i تكتبي	bi-ti-ktíb-i بتكتبي	ḥa-ti-ktíb-i حتكتبي	i-ktíb-i اكتبي
3rd	masculine	kátab كتب	yí-ktib يكتب	bi-yí-ktib بيكتب	ḥa-yí-ktib حيكتب
	feminine	kátab-it كتبت	tí-ktib تكتب	bi-tí-ktib بتكتب	ḥa-tí-ktib حتكتب
Plural
1st		katáb-na كتبنا	ní-ktib نكتب	bi-ní-ktib بنكتب	ḥá-ní-ktib حنكتب
2nd		katáb-tu كتبتوا	ti-ktíb-u تكتبوا	bi-ti-ktíb-u بتكتبوا	ḥa-ti-ktíb-u حتكتبوا	i-ktíb-u اكتبوا
3rd		kátab-u كتبوا	yi-ktíb-u يكتبوا	bi-yi-ktíb-u بيكتبوا	ḥa-yi-ktíb-u حيكتبوا

This paradigm shows clearly the reduction in the number of forms:

• The thirteen person/number/gender combinations of Classical Arabic have been reduced to eight, through the loss of dual and feminine-plural forms. (Some varieties still have feminine-plural forms, generally marked with the suffix -an, leading to a total of ten forms. This occurs, for example, in Iraqi Arabic and in many of the varieties of the Arabian peninsula.)
• The system of suffix-marked mood distinctions has been lost, other than the imperative. Egyptian Arabic and many other "urban" varieties (e.g. Moroccan Arabic, Levantine Arabic) have non-past endings -i -u inherited from the original subjunctive forms, but some varieties (e.g. Iraqi Arabic) have -īn -ūn endings inherited from the original indicative. Most varieties have also gained new moods, and a new future tense, marked through the use of prefixes (most often with an unmarked subjunctive vs. an indicative marked with a prefix, e.g. Egyptian bi-, Levantine b-, Moroccan ta-/ka-). Various particles are used for the future (e.g. Egyptian ḥa-, Levantine raḥ-, Moroccan ɣa(di)-), derived from reduced forms of various verbs.
• The internal passive is lost almost everywhere. Instead, the original reflexive/mediopassive augmentations (e.g. Forms V, VI, VII) serve as both reflexive and passive. The passive of Forms II and III is generally constructed with a reflex of Forms V and VI, using a prefix it- derived from the Classical prefix ta-. The passive of Form I uses either a prefix in- (from Form VII) or it- (modeled after Forms V and VI). The other forms often have no passive.

In addition, Form IV is lost entirely in most varieties, except for a few "classicizing" verbs (i.e. verbs borrowed from Modern Standard Arabic).

See varieties of Arabic for more information on grammar differences in the spoken varieties.