phonologymorphology

Phonology-morphology is the study of the interaction between phonology and morphology in the structure and realization of words. It includes how morphemes are realized as sound (morphophonology), how phonological processes apply at morpheme boundaries, and how morphemes can have multiple phonological realizations (allomorphy). The focus is on how sound structure and word-formation systems influence each other across languages.

Core topics include phonologically conditioned allomorphy, where the form of a morpheme changes depending on the phonological context; assimilation and epenthesis across boundaries; and processes such as vowel or consonant harmony that spread from one morpheme to adjacent material, or stress and intonation patterns that interact with affixation.

Common phenomena: English plural allomorphy, where the plural suffix is pronounced as [s], [z], or [ɪz] depending on the final segment of the base; German umlaut or vowel alternations that accompany plural formation; and cliticization or affixation that alters phonotactics at the word edge.

Theoretical approaches combine morphosyntax with phonology. Autosegmental and metrical phonology, as well as Optimality Theory and its variants, are used to model how morpheme boundaries condition phonological well-formedness and how alternate realizations are selected.

Typologically, some languages show extensive morphophonology with many allomorphs, while others have transparent morphologies. Studying phonology-morphology sheds light on word formation, inflectional paradigms, language acquisition, and historical sound change.