Diachronic phonological asymmetries and the variable stability of synchronic contrast

Kirkham, Sam and Nance, Claire (2022) Diachronic phonological asymmetries and the variable stability of synchronic contrast. Journal of Phonetics, 94: 101176. pp. 1-14. ISSN 0095-4470

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Abstract

This article aims to understand the development of diachronic asymmetries in phonological systems by evaluating the variability stability of synchronic contrasts. We focus on sonorant systems involving secondary palatalisation, grounded in the claim that palatalised laterals are more common than palatalised rhotics cross-linguistically. Our analysis reports acoustic and articulatory data on Scottish Gaelic, a Celtic language with a large sonorant inventory contrasting palatalised, plain and velarised phonemes across laterals, nasals and rhotics. We summarise high-dimensional dynamic characteristics of the acoustic spectrum and midsagittal tongue shape using a two-stage data reduction process and use these coefficients as inputs for training a Support Vector Machine. This trained model classifies unseen data in terms of its phonemic identity, which reveals that rhotics are classified best word-initially and worst word-finally, with nasals always classified better than laterals. We find that dynamic information substantially improves acoustic classification, but only improves articulatory classification for some sonorants. We propose that the variable synchronic stability of palatalisation contrasts complicates potential trajectories of diachronic change in Gaelic.