Nonverbal communication is usually understood as the process of communication through sending and receiving wordless (mostly visual) messages between people. Messages can be communicated through gestures and touch, by body language or posture, by facial expression and eye contact. Nonverbal messages could also be communicated through material exponential; meaning, objects or artifacts (such as clothing, hairstyles or architecture). Speech contains nonverbal elements known as paralanguage, including voice quality, rate, pitch, volume, and speaking style, as well prosodic features such as rhythm, intonation, and stress. Likewise, written texts have nonverbal elements such as handwriting style, spatial arrangement of words, or the physical layout of a page. However, much of the study of nonverbal communication has focused on face-to-face interaction, where it can be classified into three principal areas: environmental conditions where communication takes place, physical characteristics of the communicators, and behaviors of communicators during interaction.