Abstract

This study examines the validity of word-level accentedness and comprehensibility as measures of L2 pronunciation knowledge and provides methodological implications in L2 vocabulary research. Previous L2 pronunciation research has extensively evaluated sentence-level or passage-level speech in terms of intelligibility (whether listeners can correctly identify what is said), accentedness (the extent to which speech differs from an expected target-language norm), and comprehensibility (the perceived ease or difficulty of understanding speech) (e.g., Munro & Derwing, 1995a). In L2 vocabulary research, however, L2 pronunciation has received little attention (Uchihara, 2022), although being classified as an important aspect of spoken word knowledge in vocabulary frameworks (Nation, 2022).

In the present study, five American English speakers, 10 Japanese speakers of English, and 10 Chinese speakers of English produced 50 English words in several pronunciation styles, producing 2,250 audio recordings in total. The recordings were divided into 20 blocks of 25 words. Each of the 224 L1 American English listeners was randomly assigned four blocks (100 words) to evaluate for intelligibility, accentedness, and comprehensibility. That is, each recording was evaluated by at least four different listeners. Intelligibility was operationalized as transcription accuracy, whereas accentedness and comprehensibility were rated on nine-point Likert scales. A preliminary analysis, such as multi-facet Rasch analysis controlling for item difficulty and rater severity, revealed a pattern consistent with previous findings from L2 pronunciation research: greater accentedness did not necessarily correspond to lower comprehensibility even at the word level. In other words, words perceived as strongly accented could still be relatively easy for listeners to understand.

These findings support the use of word-level accentedness and comprehensibility as measures of productive spoken word knowledge, extending vocabulary assessment beyond form-meaning knowledge to how effectively learned forms can be understood in communication.