Morpheme is the smallest meaningful unit of language. It is the smallest unit in grammar. Phoneme is the smallest unit of sound. Morpheme, like phoneme, is an abstract unit, but on a higher level of abstraction. It consists of a sequence of classes of phonemes and has either lexical or grammatical meaning. A single phoneme may represent a morpheme, but they are not identical, e.g., the phoneme /z/ represents the plural morpheme in “caps” but nothing in “praise”.