This dissertation explores sociolinguistic issues surrounding the /ay/ and /au/ diphthongs on the island of Martha’s Vineyard, Massachusetts. I first present a synchronic analysis of raising and fronting, or centralization, of /ay/ and /au/ found in words such as “tight” and “house”. This study also revisits Labov's (1962, 1963, 1972a) germinal sociolinguistic work on Martha's Vineyard speech to allow for a comparison of past and present linguistic use. The current sociolinguistic analysis of these diphthongs sheds light on the diachronic process of a sound change.
Four decades ago, Labov observed that the first element of the /ay/ and /au/ diphthongs was centralized for Martha’s Vineyard men, particularly middle-aged fishermen, and correlated it with certain linguistic and social factors like identity (i.e., local heritage) and resistance to summer visitors. My previous research indicated that, in recent decades, islanders have been using mainland linguistic features as more and more new residents and tourists inundate this once tranquil maritime community. In this dissertation, I offer a more complete sociolinguistic analysis of the /ay/ and /au/ diphthongs from a new set of data from both men and women, collected in a speech community on Martha’s Vineyard.
The outcome of this investigation suggests a change in the linguistic patterns observed by Labov, away from centralization, mainly guided by the notion of the “linguistic market”. I argue in this dissertation that the linguistic change, or decentralization, of the /ay/ and /au/ diphthongs which has occurred is due to the socioeconomic restructuring and ideological changes that are taking place on the island, all of which are driven by socioeconomic factors and the linguistic market. These changes, in essence, are a result of a recognized reliance by islanders on new residents and tourists for financial stability. The acoustic and social factors are analyzed using VARBRUL to show how /ay/ and /au/ variation patterns today with various internal and external factors found to be salient in Labov’s earlier study.