Morphophonology (also morphophonemics or morphonology) is the branch of linguistics that studies the interaction between morphological and phonological or phonetic processes.
Its chief focus is the sound changes that take place in morphemes (minimal meaningful units) when they combine to form words.
The origins of morphophonology trace back to the early 20th century with foundational works in structural linguistics.
Subsequent theories, such as Autosegmental Phonology and Optimality Theory, have refined the analysis of morphophonological patterns Morphophonological analysis often involves an attempt to give a series of formal rules or constraints that successfully predict the regular sound changes occurring in the morphemes of a given language.
Morphophonology bridges the gap between morphology and phonology, offering insights into the dynamic interactions between word formation and sound patterns.
It continues to evolve as a field, integrating innovative approaches and broadening our understanding of linguistic systems globally.
[2] Braces, from a convention in set theory, tend to be used when the phonemes are all listed, as in {s, z, ɪz} and {t, d, ɪd} for the English plural and past-tense morphemes ⫽z⫽ and ⫽d⫽ above.
[3] For instance, the English word cats may be transcribed phonetically as [ˈkʰæʔts], phonemically as /ˈkæts/ and morphophonemically as ⫽ˈkætz⫽, if the plural is argued to be underlyingly ⫽z⫽, assimilating to /s/ after a voiceless nonsibilant.
Since the 1960s (in particular with the work of the generative school, such as Chomsky and Halle's The Sound Pattern of English) many linguists have moved away from making such a split, instead regarding the surface phones as being derived from the underlying morphophonemes (which may be referred to using various terminology) through a single system of (morpho)phonological rules.
The purpose of both phonemic and morphophonemic analysis is to produce simpler underlying descriptions for what appear on the surface to be complicated patterns.
The analyst attempts to present as completely as possible a system of underlying units (morphophonemes) and a series of rules that act on them, so as to produce surface forms consistent with the linguistic data.
The above example involves active morphology (inflection), and morphophonemic spellings are common in this context in many languages.