Suprasegmental Measures of Accentedness and Judgments of Language Learner Proficiency in Oral English

Abstract

In high-stakes oral proficiency testing as well as in everyday encounters, accent is the most salient aspect of nonnative speech. Prior studies of English language learners' (ELLs') pronunciation have focused on single parameters of English, such as vowel duration, fundamental frequency as related to intonation, or temporal measures of speech production. The present study addresses a constellation of suprasegmental characteristics of nonnative speakers of accented English, combining indices of speech rate, pause, and intonation. It examines relations between those acoustic measures of accentedness and listeners' impressions of second-language oral proficiency. Twenty-six speech samples elicited from iBT TOEFL ® examinees were analyzed using a KayPENTAX Computerized Speech Laboratory. Monolingual U.S. undergraduates (n = 188) judged the speakers' oral proficiency and comprehensibility. A multiple regression analysis revealed the individual and joint predictiveness of each of the suprasegmental measures. The innovative aspect of this study lies in the fact that the multiple features of accentedness were measured via instrumentation rather than being rated by judges who may, themselves, be subject to rating biases. The suprasegmental measures collectively accounted for 50% of the variance in oral proficiency and comprehensibility ratings, even without taking into consideration other aspects of oral performance or of rater predilections.THE CONSTRUCTS OF COMPREHENSIBILITY and accentedness relate in complex ways to native speaker (NS) judgments of English language learners' (ELLs') oral proficiency. No clear isomorphism has been established between degree of accentedness and comprehensibility. Speakers who succeed in reducing the degree of "foreignness" in their accents (based on expert observer judgments) may still be heard as incomprehensible by lay listeners (Munro & Derwing, 1995).

Lexical Profiles of Comprehensible Second Language Speech

“…This is because previous research on comprehensibility has chiefly focused on the phonology and fluency dimensions of L2 oral production. For instance, scalar ratings of comprehensibility appear to be associated with prosody (Kang et al, 2010) and segmental errors, especially those with high functional load (Munro & Derwing, 2006), and with pausing frequency and speaking rate (Derwing et al, 2004). There is also mounting evidence that comprehensibility is related to grammatical accuracy in L2 speech (Munro & Derwing, 1999;, such that understanding is compromised when listeners are exposed to ungrammatical utterances (Varonis & Gass, 1982).…”

“…As comprehensibility is linked to multiple linguistic domains, including phonology, fluency, lexicon, grammar, and discourse structure (e.g., Isaacs & Trofimovich, 2012;Kang et al, 2010;Munro & Derwing, 1999;Saito et al, 2015), pronunciation and fluency training should also be introduced in the context of vocabulary teaching. For instance, Field (2005) recommended focusing on word stress as a part of vocabulary teaching, arguing that "the responsibility for presenting [lexical stress] falls as much on the vocabulary teacher as on the pronunciation teacher, and the oral practice of new items should include attention to their stress pattern" (p. 420).…”

“…Despite the multidimensional nature of speaking, only several of its components have been extensively researched. For instance, several studies have examined which pronunciation and fluency aspects of L2 oral production relate to rater-based measures, such as comprehensibility or ease of understanding (e.g., Isaacs & Trofimovich, 2012;Kang, Rubin, & Pickering, 2010). By comparison, little research has focused on lexical characteristics of L2 speech especially from the perspective of comprehensibility.…”

Differential effects of instruction on the development of second language comprehensibility, word stress, rhythm, and intonation: The case of inexperienced Japanese EFL learners

“…In addition, suprasegmental errors tend to hinder listeners' assessment of L2 speech more directly than segmentals do (Anderson-Hsieh, Johnson, & Koehler, 1992;Kang, Rubin, & Pickering, 2010). Suprasegmental-based instruction is thus likely more effective than segmentalbased instruction, especially for the development of comprehensibility (Derwing et al, 1998;Gordon, Darcy, & Ewert, 2013).…”

“…According to cross-linguistic reviews (e.g., Saito, 2014), Japanese learners of English are reported to have several L1-L2 transfer problems at the suprasegmental level, which consequently leads to listeners' impaired understanding of their speech (e.g., Hanh, 2004;Kang et al, 2010). …”