The duality of patterning refers to the way in which speech can be broken down into meaningful discrete components commonly called morphemes that in turn can be further decomposed into

minimal distinctive though meaningless discrete units called phonemes.

Higher levels of language organization (morphology, syntax, and semantics) govern the combination of these individually meaningless phonemes into meaningful elements.

According to Charles F. Hockett and other linguists, this property of duality (a finite number of elements combining to produce an infinite number of meaning) is a crucial property of human languages as it allows the expression of an infinite number of meaningful language structures.

Next page: First layer – Arbitrariness and Discreteness