3.2   Morphs and Allomorphs(词素变体)

    Morphemes are abstract units, which are realized in speech by discrete units (具体单位) known as morphs (形素). 'They are actual spoken, minimal carriers of meaning' (Bolinger and Sears 1981:43). In other words the phonetic or orthographic strings(语音串或拼写字串) or segments (切分成分；节) which realize morphemes are termed 'morphs' (Bauer 1983:15). The morpheme is to the morph what a phoneme (音位) is to a phone (音素). Most morphemes are realized by single morphs like bird, tree, green , sad, want, desire, etc. . These morphemes coincide (巧合) with words as they can stand by themselves and function freely in a sentence. Words of this kind are called mono-morphemic words. Some morphemes, however, are realized by more than one morph according to their position in a word. For instance, the morpheme of plurality {-s} has a set of morphs in different sound context, e. g. in cats /s/, in bags /z/, in matches /iz/. The alternates (作为替换的事物) /s/, /z/ and /iz/ are three different morphs. The same is true of the link verb morpheme {be}. Its past tense is realized by two distinct orthographic forms was , were, each of which happens to be a word-form, realizing {preterit} and {singular}, and {preterit} and {plural} respectively and each has its own phonetic form /woz/ or /wə:/. Therefore, both was, were and their phonetic forms /woz/ and /wə: / are morphs (See discussion in Bauer, p15).

    An allomorph refers to a member of a set of morphs, which represent one morpheme. Just as we class phones(音素) together as allophones (音位变体) of a single phoneme(音位), so we class morphs together as allomorphs of a single morpheme. Take the plural morpheme {-s} again. Phonetically, it is realized by /s/, /z/, /iz/, all of which are allomorphs. In English, many morphemes can have more than one allomorph, particularly those freestanding morphemes which are functional words in their own right. Once they occur in connected speech, they may be realized by different forms, depending on whether they are accented or weakened (Look at the data in the table).

 

Morpheme	Allomorph
	Strong	Weak
{am}	/aem/	/əm/, /m/
{ was}	/woz/	/WəZ/
{have }	/haev/	/həv/, /v/
{would }	/wud/	/wəd/, /əd/, /d/
{he}	/hi:/	/i:/, /i/
{his}	/hiz/	/iz/
{for}	/fo:/	/fə/
{to}	/tu:/	/tu/, /tə/

    Then what is the difference between morphs and allomorphs? The relationship can be illustrated by the diagram below.

                   Morpheme

                    {would}

morph    morph    morph    morph   → all

/wud/       /wəd/       /əd/         /d/