Summary

Allomorphy and syncretism are both deviations from the one-to-one relationship between form and meaning inside the linguistic sign as postulated by Saussure as well as from the ideal of inflectional morphology as stipulated in the canonical approach by Corbett. Instances of both phenomena are well documented in all Romance languages. In inflection, allomorphy refers to the use of more than one root/stem in the paradigm of a single lexeme or to the existence of more than one inflectional affix for the same function. Syncretism describes the existence of identical forms with different functions in one and the same paradigm.

Verbs exhibiting stem allomorphy are traditionally called irregular, a label that describes the existence of unexpected and, sometimes, unpredictable forms from a learner’s perspective. Extreme forms of allomorphy are called suppletion, for which traditional accounts require two or more etymologically unrelated roots/stems to coexist within the paradigm of a single lexeme. Allomorphy often originates in sound change affecting only stems in a certain phonological environment. When the phonological conditioning of the stem allomorph disappears, which is frequently the case, its distribution within the paradigm may become purely morphological, thus constituting a morphome in the sense of Aronoff.

Recurrent patterns of syncretism may also be considered morphomes. Whereas syncretism was quite rare in Latin verb morphology, Romance languages feature it to much greater, if different, degrees. In extreme cases, syncretism patterns become paradigm-structuring in many Gallo-Romance varieties, as is the case in the verb morphology of standard French, where almost all forms are syncretic with at least one other.