Morpheme：a morpheme can be understood as the minimal unitof language that has its own meaning, a unit that cannot be divided into further smaller units without destroying or drastically altering the meaning, whether it is lexical or grammatical, that is, morpheme is both a grammatical and a semantic concept.Besides, words may consist of one morpheme or more than one morpheme.For instance, the word “barks”consists of two morphemes in orthographic forms: “bark”and “-s”, neither of which can be further divided into smaller meaning units.
Allomorph:Some morphemes have a single form in all contexts, such as “dog”, “cat”, etc. Some others may have considerable variation, i. e. a morpheme may have alternate shapes or phonetic forms, which are called the allomorph, that is, those morphs that represent the same morpheme are called the allomorphs of the same morpheme. For example, the allomorphs of the plural morpheme {-s, -z, -iz, -ai, -i:, -n, -?}. Some morphemic shapes represent different morphemes and thus have different meanings, for example, the morphemic shape “-s” can express plurality in tables, person/finiteness in talks, and case in boy’s.
Morphophoneme refers to the phoneme (or string of phonemes) that constitutes the various allomorphs of a morpheme. Generally speaking, the concept of morphopheme adds a grammatical meaning to the concept of phoneme. For example, as to the phoneme /s/, it is in fact a configuration of allomorphs of different morphemes, such as the plural morpheme and the 3rdperson present simple morpheme. Therefore, we would regard this phoneme as a morphophoneme represented as /s/.
