“Dim Sôn am Dduw na Dyn”: Ar drywydd yr ‘U Ogleddol’ yng nghanolbarth Cymru (“No Mention of a Duw or a Dyn”: Investigating the ‘Northern U’ vowel in mid-Wales)

The high central vowel, or the ‘northern u’ as it is informally called, is well known to be a characteristic feature of northern Welsh. Generally in north Wales, a clear contrast is heard between pairs such as ‘tŷ’ / ‘ti’ and ‘sur’ / ‘sir’. Conversely, since this contrast is neutralised in the south, these words are homophones, and are always pronounced with the high front vowel ‘i’. The main aim of this study therefore is to analyse quantitatively the way in which this contrast between ‘northern u’ and ‘southern i’ is lost in parts of mid-Wales. Consequently, the results will show the complex patterns of variation that arise in one particular ‘transition zone’, namely the Tywyn district, and demonstrate how speakers’ use of the high central vowel in this area is conditioned to a considerable extent by specific linguistic factors. Finally, this article will postulate that the interchange between the high front and the high central vowels is also related to variation in the length of diphthongs, and the implications of this theory will be probed.