David Crystal OBE FBA FLSW (born July 6, 1941) is a linguist, academic and author.

Crystal was born in Lisburn, Northern Ireland. He grew up in Holyhead, North Wales, and Liverpool, England, where he attended St Mary's College from 1951.

Crystal studied English at University College London between 1959 and 1962. He was a researcher under Randolph Quirk between 1962 and 1963, working on the Survey of English Usage. Since then he has lectured at Bangor University and the University of Reading. He is currently an honorary professor of linguistics at Bangor. His many academic interests include English language learning and teaching, clinical linguistics, forensic linguistics, language death, "ludic linguistics" (Crystal's neologism for the study of language play), English style, Shakespeare, indexing, and lexicography. He is the Patron of the International Association of Teachers of English as a Foreign Language (IATEFL) and honorary vice-president of the Society for Editors and Proofreaders (SfEP). He has also served as an important editor for Cambridge University Press.

David (Hebrew: דָּוִד, דָּוִיד, Modern David Tiberian Dāwîḏ; ISO 259-3 Dawid; Strong's Daveed; beloved; Arabic: داوود‎ or داود‎ Dāwūd) was, according to the Hebrew Bible, the second king of the United Kingdom of Israel and, according to the Gospel of Matthew and the Gospel of Luke, an ancestor of Jesus. David is seen as a major Prophet in Islamic traditions. His life is conventionally dated to c. 1040–970 BC, his reign over Judah c. 1010–1003 BC,^{[citation needed]} and his reign over the United Kingdom of Israel c. 1003–970 BC.^{[citation needed]} The Books of Samuel, 1 Kings, and 1 Chronicles are the only sources of information on David, although the Tel Dan stele records "House of David", which some take as confirmation of the existence in the mid-9th century BC of a Judean royal dynasty called the "House of David".

David is very important to Jewish, Christian and Islamic doctrine and culture. In Judaism, David, or David HaMelekh, is the King of Israel, and the Jewish people. Jewish tradition maintains that a direct descendant of David will be the Messiah. In Islam, he is known as Dawud, considered to be a prophet and the king of a nation. He is depicted as a righteous king, though not without faults, as well as an acclaimed warrior, musician, and poet, traditionally credited for composing many of the psalms contained in the Book of Psalms.