Allomorphy

Allomorphy is the phenomenon whereby a single morpheme is realised by two or more distinct forms, called allomorphs, whose distribution may be phonologically, morphologically, or lexically conditioned.

Definition

Allomorphy is the systematic alternation in the phonological shape of a morpheme across its occurrences, where the alternants (allomorphs) stand in complementary or conditioned distribution.

Scope

This topic covers the variation of morphemes into alternant forms: the kinds of conditioning that govern allomorph selection (phonological, morphological, lexical, and suppletive), the distinction between regular morphophonemic alternation and arbitrary allomorphy, and the analytic devices used to capture it. It does not treat morpheme identification in general or paradigm-level patterns such as syncretism, which belong to neighbouring topics.

Core questions

• What conditions the choice between competing allomorphs of a morpheme?
• How is phonologically conditioned allomorphy distinguished from morphologically and lexically conditioned allomorphy?
• When does an alternation belong to phonology rather than to morphology?
• How should suppletion, the extreme case of unrelated allomorphs, be analysed?

Key concepts

• allomorph
• phonological conditioning
• morphological conditioning
• lexical conditioning
• suppletion
• morphophonemic alternation

Key theories

Conditioned allomorph selection

The account that allomorphs are listed alternants chosen by their environment, with phonological conditioning at one end, grammatical or lexical conditioning in the middle, and fully arbitrary suppletion at the other.

Morphophonemic rule analysis

The generative treatment under which a single underlying form is mapped to its surface allomorphs by phonological or morphophonemic rules, reserving listing for alternations that resist rule-based derivation.

History

Allomorphy was a central concern of post-Bloomfieldian morphophonemics, which sought to derive surface alternants from underlying forms. Generative phonology, especially after Chomsky and Halle, absorbed much regular allomorphy into the phonological component, leaving morphology to handle the residue. Carstairs-McCarthy (1987) examined the limits on allomorphic variation within inflection, and subsequent work has debated how much allomorphy is phonological versus genuinely morphological.

Debates

The phonology-morphology boundary in alternation

Whether a given alternation should be derived by phonological rule or listed as morphologically conditioned allomorphy; the answer affects the division of labour between the two components of grammar.

Key figures

• Andrew Carstairs-McCarthy
• Andrew Spencer
• Martin Haspelmath

Seminal works

• carstairsmccarthy1987
• spencer1991
• haspelmathsims2010

Frequently asked questions

What is an example of allomorphy in English?

The regular plural suffix has three phonologically conditioned allomorphs: /s/ in 'cats', /z/ in 'dogs', and /ɪz/ in 'horses'. The choice is determined by the final sound of the noun stem.

How is suppletion different from ordinary allomorphy?

Suppletion is the extreme case where the alternants share no phonological material, as in 'go' versus 'went'. Ordinary allomorphy involves phonologically related forms, whereas suppletive allomorphs must simply be listed.