Measuring phonetic convergence : segmental and suprasegmental speech adaptations during native and non-native talker interactions

Phonetic convergence (PC) is speech specific accommodation characterized by an increase in similarity in a dyad’s speech patterns due to an interaction. Previous research has demonstrated that PC occurs in dyads during various interactive tasks (e.g. map completion and picture matching) and in cross-linguistic conditions (e.g. dyads who speak the same or different native language) (Pardo, 2006; Kim et al., 2011). Studies suggest that speakers who are closer in linguistic distance (i.e. share the same native language) are more likely to converge than speakers who are far apart (i.e. speak different native languages) (Kim et al, 2011). However, Interdialectal conditions where speakers use different national dialects of the same language have been studied to a far lesser extent (Babel, 2010). Similarly, studies have examined both segmental and suprasegmental features that are susceptible to PC but rhythm has not been studied extensively (Krivokapic, 2013; Rao et al., 2011). Though initial studies postulated that PC is the result of either automatic or social processes, more current research suggests that a combination of both kinds of processes may be better able to account for PC (Goldinger, 1997; Shepard et al., 2001; Babel, 2009a). The current dissertation uses novel measures such as Interlocutor Similarity and EMS + centroid to implicate global properties of vowels and rhythm respectively as acoustic correlates of PC. Moreover, it finds that speakers showed both convergence and divergence in vowels and rhythm as moderated by their language background. Close interactions between native speakers of American English (AE) resulted in convergence whereas interdialectal interactions (between AE and Indian English speakers) and mixed language interactions (between native and non-native speakers of AE who are native speakers of SP) resulted in both convergence and divergence. The results from this study may shed light on how speakers attenuate the highly variable nature of speech by adapting speech patterns to aid intelligibility and information sharing (Shepard et al., 2001) and that this attenuation is moderated by social demands such as identity and cultural distinctiveness.