This dissertation presents a sociophonetic analysis of vowel phonemes descended from Middle English /ɔ:/ and /ɔu/ (MOAN-MOWN) in Lowestoft English, the East Anglian variety spoken in the UK’s easternmost town. These phonemes started to merge under a single GOAT vowel in the vast majority of English varieties during the 16th or 17th century, but this collapse is reported as progressing in some East Anglian English varieties only since the 1970s. Whether the merger is complete in Lowestoft, which straddles – both linguistically and administratively – the regional divide between varieties with a merger versus a distinction, remains uncertain.

I interrogate this issue and empirically evaluate an early claim by Trudgill (1988b) that the merging of MOAN and MOWN may have been delayed in some varieties of East Anglian English by a pre-existing merger between the MOAN and GOOSE vowels. This dissertation utilises and statistically models data from both production and perception for a holistic view of merger.

Production data come from 30 interviews in which production of minimal pairs, word lists and spontaneous speech was elicited for both MOAN-MOWN and MOAN-GOOSE. Dynamic formant trajectories are analysed statistically using generalised additive mixed models to identify merger in production. Three perception tasks – AX discrimination, minimal pair judgements and vowel-continua categorisation – are used to identify perceptual merger, and detect any asymmetries synonymous with near merger.

Results suggest that long-term resistance to the MOAN-MOWN merger is derived from structural incompatibility between the incoming GOAT form and the East Anglian system. A MOAN-MOWN merger is rapidly progressing amongst younger speakers, but remains incomplete. The MOAN-GOOSE merger is found to have never reached completion, with full distinction in the youngest generation in contrast to full or near merger in older speakers, who variably distinguish these via lowered F2 in MOAN. These findings show near/variable merger to play a powerful role in mitigating sound change.