The vowel /əː/ ao in Gaelic dialects

Abstract

This paper examines the development of the Old Irish diphthongs */ai/, */oi/, */ui/ in later varieties of the Gaelic languages. These are generally accepted to have merged as a single phoneme by the end of the Old Irish period (c. 900). In all modern varieties the regular reflex of this phoneme is a long monophthong, represented orthographically as <ao>. There are three main developments: (a) in southern Irish <ao> has merged with /eː/ and/or /iː/; (b) in southern Scottish and Manx varieties <ao> remains a mid-central vowel, may be fairly fronted and may perhaps have weak rounding; and there is merger between /əː/ representing <ao> and reflexes of earlier */aɣ/; (c) in northern Scottish and northern Irish varieties <ao> is realized as a high back unrounded vowel /ɯː/, which is contrastive with mid back unrounded /ɤː/ representing earlier */aɣ/ (these may merge with /iː/ and /eː/ in Ulster). Building on suggestions of earlier scholars, it is argued that it is the developments of */əː/ are explained by its anomalous position in the phonological system of earlier varieties of Gaelic, and its interactions with the palatalization contrast of the consonant system.