Vowel nasalisation in Scottish Gaelic: No evidence for incomplete neutralisation in initial mutation

Abstract

The existence of incomplete neutralisation in connection with processes like final devoicing is well-known, but little work exists on typologically more uncommon morphological processes such as Celtic initial mutation. This paper reviews the small existing literature on incomplete neutralisation in initial mutation, showing that no convincing evidence has been found so far, and presents a new nasal airflow study on four speakers of Scottish Gaelic that adds to these negative results.Radical initial /p/ and /m/ in Scottish Gaelic are neutralised to [v] under the lenition mutation. Vowels following radical initial /m/ in Scottish Gaelic may display either categorical phonological nasalisation or gradient phonetic nasalisation. Nasal airflow in items with radical initial /p/ and /m/ is measured in order to determine whether the degree of vowel nasalisation after [v] in lenited forms is sensitive to the identity of the corresponding radical consonant. LME model comparison finds that only categorical phonological nasalisation, and not gradient phonetic nasalisation, may be subject to morphological conditioning. This is at odds with widespread existing findings for processes such as final devoicing, where the gradient phonetic properties of neutralised segments display sensitivity to paradigmatic effects.The absence of incomplete neutralisation in initial mutation is consistent with recent proposals that restrict the types of morphophonological processes that may bring about incomplete neutralisation to highly transparent, phonetically natural processes involving conflict between word-specific morphological pressures and language-wide phonotactic constraints. These findings can inform us about the structure of the mental lexicon and the derivation of morphologically complex forms.