The acoustics of three-way lateral and nasal palatalisation contrasts in Scottish Gaelic.

This paper presents an acoustic description of laterals and nasals in an endangered minority language, Scottish Gaelic (known as "Gaelic"). Gaelic sonorants are reported to take part in a typologically unusual three-way palatalisation contrast. Here, the acoustic evidence for this contrast is considered, comparing lateral and nasal consonants in both word-initial and word-final position. Previous acoustic work has considered lateral consonants, but nasals are much less well-described. An acoustic analysis of twelve Gaelic-dominant speakers resident in a traditionally Gaelic-speaking community is reported. Sonorant quality is quantified via measurements of F2-F1 and F3-F2 and observation of the whole spectrum. Additionally, we quantify extensive devoicing in word-final laterals that has not been previously reported. Mixed-effects regression modelling suggests robust three-way acoustic differences in lateral consonants in all relevant vowel contexts. Nasal consonants, however, display lesser evidence of the three-way contrast in formant values and across the spectrum. Potential reasons for lesser evidence of contrast in the nasal system are discussed, including the nature of nasal acoustics, evidence from historical changes, and comparison to other Goidelic dialects. In doing so, contributions are made to accounts of the acoustics of the Celtic languages, and to typologies of contrastive palatalisation in the world's languages.