Fluency, comprehensibility, and accentedness in L2 speech: Examining the role of visual and acoustic information in listener judgments

Abstract

The purpose of the present study was to examine (a) the effects of audio-visual information and (b) the role of temporal measurements associated with the perceptual ratings of fluency, accentedness, comprehensibility, pronunciation, and oral proficiency in second language (L2) speech samples of International Teaching Assistants (ITAs). American undergraduate students randomly assigned to audiovisual and audio-only (without seeing the speaker) conditions rated the two-minute speech samples of five ITAs on a seven-point scale. For acoustic analysis, several temporal measurements were used that were hypothesized to have an association with the ratings. Findings revealed that listeners without visual information judged L2 speech as less fluent and more accented although no significant difference in comprehensibility was found. L2 speakers were also judged to have better pronunciation and higher oral proficiency when the recordings were presented in video mode. The findings further indicated that among the acoustic measures examined, articulation rate was found to be associated with perceptual ratings. Implications for ITA training and language testing and assessment are discussed.