L2 speech intelligibility

O 'Brien, 2013*).Therefore, discussion on speech intelligibility is needed to better understand such a multifaceted construct both conceptually and methodologically.Following Munro and Derwing's (1995*) and Derwing and Munro's (1997*) seminal work, three speech constructs have come to dominate the L2 pronunciation literature: intelligibility, comprehensibility, and accentedness.Intelligibility is referred to as the degree to which a listener actually understands a speaker's intended message, accentedness as phonological differences between L2 and target language, and comprehensibility as how easy or difficult a speaker is to understand, focusing on processing efforts.In other words, intelligibility can be defined as the accuracy to which a listener can identify the intended utterances produced by a speaker.This distinction has led to a wide acceptance that these constructs are at least partially independent (Derwing & Munro, 1997).That is, an L2 speaker's speech can be heavily accented but still be largely intelligible, although some research suggests that intelligibility usually decreases as the degree of accent increases (Rogers et al., 2004).On the other hand, a lack of intelligibility does not necessarily indicate a weak accent.In fact, speakers who are easily understood may still be perceived as having a strong accent (Kang et al., 2018*).Another important characteristic of intelligibility is that it serves a vital communicative function in our everyday interactions, and the success of information transfer depends on the mutual intelligibility between the speaker and the listener.Understanding is an interactive process that requires engagement from both speakers and listeners, rather than relying solely on one party (Smith & Nelson, 2019).Given that communication is a collaborative activity requiring active participation from both speakers and listeners, sharing responsibility for a successful interaction is key to global communication (Clark & Wilkes-Gibbs, 1986; Derwing et al., 2014*).Put differently, a speaker's intelligibility can depend on situational, social, and cultural factors (Smith & Nelson, 2019).Much research has also examined listeners' language and linguistic backgrounds that affect L2 intelligibility.Gass and Varonis (1984*) demonstrated listeners' language experiences (e.g., familiarity with the topic, accent, speaker) were strongly correlated with their judgments of L2 intelligibility.Note that while the authors used the term comprehensibility, their measure was more in line with intelligibility measures.One factor that also contributes to greater tolerance of listeners is known as "the interlanguage speech intelligibility benefit (ISIB)" (Bent & Bradlow, 2003).This asserts that L2 listeners may have benefits in interpreting specific acoustic-phonetic features of an L2 that are matched with their own L1s.Although some studies showed mixed results (Major et al., 2002) or minimal effects of listeners' L1 (Munro et al., 2006*), other recent studies have demonstrated consistent shared-L1 effects among L2 listeners with certain L1 backgrounds, i.e., especially among listeners from outer circle countries (e.g., India or South Africa) where English is spoken as an official and second language (e.g., Kang et al., 2019Kang et al., , 2023;; Shin et al., 2021).To explain this, some scholars have argued that shared L1 may not directly influence understanding but may do so in more complex and indirect ways (Miao, 2023).Currently, research on L2 intelligibility seems to be at a turning point, expanding its scope and depth of understanding.Previously, understanding diverse accented speech was a central concern in the globalized world; thus, most research primarily investigated this construct based on human judgments.However, with the rise of interaction with artificial intelligence (AI) chatbots (Labadze et al., 2023), learners or speakers are now at the stage of prioritizing intelligible speech even in their communications with AI (Moussalli & Cardoso, 2020*).Furthermore, the evolution of automatic speech recognition (ASR) capabilities in AI technology has spurred an increase in research focused on ASR-based L2 intelligibility (Inceoglu et al., 2023*).This means that we are entering the initial stage of a new era in speech intelligibility.Accordingly, the current timeline on L2 intelligibility is timely and appropriate at both practical and pedagogical levels.The field stands to benefit from carefully compiled and scrutinized studies, along with their key findings.Note that the current research timeline stands out distinctly from its predecessor.While Munro & Derwing (2011) examined studies concerning classroom pronunciation instruction, with a focus on Derwing, T. M., & Munro, M. J. (1997).Accent, intelligibility, and comprehensibility: Evidence from four L1s.Studies in Second Language Acquisition, 19(1), 1-16.Derwing and Munro extended their precursor work (MUNRO & DERWING, 1995) to include English accents from speakers of four L1 backgrounds: Cantonese, Japanese, Polish, and Spanish.This study also took into account speaker proficiency and listener familiarity.Results supported the previous study that regardless of speaker proficiency, accentedness, comprehensibility, and intelligibility still emerged as independent constructs, although the weight of linguistic features contributing to these constructs differed.Moreover, the study found that accent identification ability was influenced by listeners' accent familiarity.