A system that relates sounds or gestures to meaning. Language is: symbolic and arbitrary - cat means nothing about cats, structured - syntax, shows displacement - can talk about present past and future not just present, generatively - in nite number of possibilities using words + structure. Concerns the study of individual sounds in a language i. e blabber b/la/b//er: morphology. Smallest unit of meanings in a word i. e. sweatshirt - sweat + shirt. Study of words and their meanings: syntax. Rules used to structure language (grammar: pragmatics. How people use language to communicate effectively. Newborn infants show preference for speech over complex non speech sounds. Infants can distinguish between phonemes as early as 1 month after birth. Studies canadian infants from english speaking families. Infants ranging from 2-7 months listened longer to speech sounds than to similar non speech sounds. Present french babies with two foreign languages. Wanted to see if babies knew they were foreign.