Iosad, Pavel. 2023. Mutation in Celtic. In Peter Ackema, Sabrina Bendjaballah, Eulàlia Bonet & Antonio Fábregas (eds.), The Wiley Blackwell companion to morphology. Oxford: Wiley-Blackwell.
The Celtic languages are characterized by an elaborate system of alternations of word-initial segments, traditionally known as ‘consonant mutations’. Although historically they arose from across-the-board phonological sandhi, they are now deeply embedded in morphosyntactic processes. They are relatively phonologically coherent, but also non-concatenative, and sensitive to a wide range of lexical, morphological, syntactic and semantic factors. As a result, Celtic mutations present an important test bed for theories of word structure and its interactions with both phonology and syntax.