:"This article is about a linguistic term. See
Pseudomorphfor another meaning of the word."
An allomorph is a
linguisticsterm for a variant form of a morpheme. The concept occurs when a unit of meaning can vary in sound (phonologically) without changing meaning. It is used in linguistics to explain the comprehension of variations in sound for a specific morpheme.
Allomorphy in English Suffixes
English has several morphemes that vary in sound but not in meaning. Examples include the past tense and the plural morphemes.
For example, in English, a past tense morpheme is "-ed". It occurs in several allomorphs depending on its phonological environment, assimilating voicing of the previous segment or inserting a
schwawhen following an alveolar stop:
* as IPA|/ɪd/ in verbs whose stem ends with the alveolar stops IPA|/t/ or IPA|/d/, such as 'hunted' IPA|/hʌntəd/ or 'banded' IPA|/bændəd/
* as IPA|/t/ in verbs whose stem ends with voiceless phonemes other than IPA|/t/, such as 'fished' IPA|/fɪʃt/
* as IPA|/d/ in verbs whose stem ends voiced phonemes other than IPA|/d/, such as 'buzzed' IPA|/bʌzd/
Notice the "other than" restrictions above. This is a common fact about allomorphy: if the allomorphy conditions are ordered from most restrictive (in this case, after an alveolar stop) to least restrictive, then the first matching case usually "wins". Thus, the above conditions could be re-written as follows:
* as IPA|/ɪd/ when the stem ends with the alveolar stops IPA|/t/ or IPA|/d/
* as IPA|/t/ when the stem ends with voiceless phonemes
* as IPA|/d/ in verbs
The fact that the IPA|/t/ allomorph does not appear after stem-final IPA|/t/, despite the fact that the latter is voiceless, is then explained by the fact that IPA|/əd/ appears in that environment, together with the fact that the environments are ordered. Likewise, the fact that the IPA|/d/ allomorph does not appear after stem-final IPA|/d/ is because the earlier clause for the IPA|/əd/ allomorph takes priority; and the fact that the IPA|/d/ allomorph does not appear after stem-final voiceless phonemes is because the preceding clause for the IPA|/t/ takes priority.
Irregular past tense forms, such as "broke" or "was/ were", can be seen as still more specific cases (since they are confined to certain lexical items, like the verb "break"), which therefore take priority over the general cases listed above.
Allomorphy can also exist in stems or roots, as in Classical
There are three allomorphs of the stem: IPA|/vak/, IPA|/va/ and IPA|/vag/. The allomorphs are conditioned by the particular case-marking suffixes.
The form of the stem IPA|/vak/, found in the nominative singular and locative plural, is the etymological form of the morpheme. Pre-Indic palatalization of
velarsresulted in the variant form IPA|/va/, which was initially phonologically conditioned. This conditioning can still be seen in the Locative Singular form, where the IPA|// is followed by the high front vowel IPA|/i/.
But subsequent merging of IPA|/e/ and IPA|/o/ into IPA|/a/ made the alternation unpredictable on phonetic grounds in the Genitive case (both Singular and Plural), as well as the Nominative Plural and Instrumental Singular. Hence, this allomorphy was no longer directly relatable to phonological processes.
Phonological conditioning also accounts for the IPA|/vag/ form found in the Instrumental Plural, where the IPA|/g/ assimilates in voicing to the following IPA|/b/.
The term was originally used to describe variations in chemical structure. It was first applied to language (in writing) in 1948, by E.A. Nida in Language XXIV. [ Oxford English Dictionary Online: Entry 50006103. Accessed: 2006-09-05 ]
*cite book|title= Principles and Methods for Historical Linguistics |author= Jeffers, Robert J. and Lehiste, Ilse |year=1979
publisher= MIT Press |
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