The sound patterns of language
Each individual will not pronounce the word me in a physically identical manner one very occasion. Obvious differences occur when that individual is shouting, is suffering from a bad cold or is asking fora sixth martini. Given this vast range of potential differences in the actual physical production of a speech sound,how do we manage consistently to recognize all those versions of meas the form [mi], and not [ni]or [si] or [ma] or[mo]or something else entirely? The answer to that question is provided to a large extent by the study of phonology.