The Influence of Turkish Regional Dialects on L2 English Speech Production

Aksu, Bahar and Kirkham, Sam and Harding, Luke (2022) The Influence of Turkish Regional Dialects on L2 English Speech Production. PhD thesis, Lancaster University.

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Abstract

It is widely known that the development of L2 speech perception and production is influenced by the L1 phonological system (Zampini, 2008). Current models of L2 speech learning propose a number of mechanisms that explain such phenomena, such as the existence of a shared L1-L2 phonological space (e.g., Speech Learning Model [SLM]; Flege, 1995), early perceptual attunement to L1 phonology (Perceptual Assimilation Model L2 [PAM-L2]; Bohn & Best, 2007), and the idea that the L1 represents the initial state for L2 learning (Second Language Linguistic Perception [L2LP]; Escudero, 2005). Despite strong theoretical understandings of how L1 phonology influences L2 production, our knowledge of how between-speaker variation in the L1 influences the L2 remains less well established. For example, research confirms the influence of L1 regional dialects on L2 speech perception (Chládková & Podlipský 2011; Escudero & Williams 2012), but research focusing on the influence of L1 regional dialects on L2 speech production has revealed only partial effects (Marinescu, 2012; Simon et al. 2015). There is a clear need, then, for further investigation into the precise dynamics of how structured L1 variation influences the outcomes of L2 speech production. This thesis investigates the influence of regional dialect on L2 English speech production focusing specifically on L1 Turkish speakers from two different regional dialect backgrounds. First, I carried out acoustic phonetic analysis investigating the nature of regional variation between İstanbul Turkish and Trabzon Turkish speakers (N=28) in terms of the production of vowels, and the voiced affricate. Second, I examined the role of regional dialect in L2 English speech production by comparing the same dialect groups of Turkish together with Standard Southern British English (SSBE) speakers. Fourteen speakers for each dialect group (N=42) aged 18-35 were recruited for speech production experiments in Trabzon, İstanbul, and Lancaster. The acoustic phonetic analysis of regional variation in Turkish shows that the production of low vowels and fronting mechanisms differ between the two target regions. However, high vowels, acoustic correlates of lip rounding, and durational features show similarities between the two regional dialects. In terms of voiced affricate production in Turkish, there are no significant L1 dialect differences, but there remain overall effects of word position and vowel context. I interpret these findings according to the socio-phonetic/linguistic contexts of the target regions. The findings on L1 dialect variation are then used to investigate differences in L2 speech production. There is no regional dialect influence on L2 speech production of the voiced affricate, which is expected given the lack of differences between dialects in L1 Turkish. Yet, the results find that acoustic realization of /dʒ/ is different between L1 Turkish and SSBE speakers. There is evidence of L1 dialect effects on L2 production of English vowels, such that the tense -lax contrast /ɪ/ -/i:/ in L2 English is smaller in magnitude for speakers of Trabzon than speakers of İstanbul, with both groups showing smaller distinctions than SSBE speakers. The /ɜː/ vowel shows L1 dialect effects on L2 English despite the lack of regional dialect differences in the L1. The regional dialect differences found for /ʌ/ and /æ/ vowels in the L1 are not found in L2 English, yet the allophones of /ʌ/ in L1 – [ɑ:] and [ɒ] – are influenced by the regional dialect in L2 English production. In summary, the results demonstrate the variable effects of L1 regional dialects on L2 speech production. The influence of L1 regional dialect was observed in L2 English production of vowels, in line with the predictions of L2LP; however, there were no significant differences in the production of voiced affricates. Overall, these analyses suggest that L1 regional dialect can shape L2 speech production patterns, but that this occurs to different degrees for different phonemes. In summary, this thesis advances our understanding of cross dialectal and cross linguistic influences in L2 speech production, while also providing important documentation of regional phonetic variation in Turkish.