Effects of training with sentences at varied speaking rates on native English speakers’ perception of Japanese vowel length

Abstract

In training non-native speakers to perceive difficult second language (L2) phonetic contrasts, providing variation in speakers and phonetic contexts helps the formation of L2 categories [Pisoni and Lively, in Speech Perception and Linguistic Experience (1995), pp. 433–459. The present study tested the hypothesis that high stimulus variability in speaking rate would have positive effects for L2 learners. Native English speakers’ ability to identify Japanese vowel length was examined with three types of training: slow-only, fast-only, and slow-fast. Their perceptual abilities were measured with a pretest and posttest and compared with a control group that was not trained. Test stimuli were sentences containing Japanese disyllables spoken at three rates (slow, normal, fast). Participants were trained to identify the length of the second vowel of disyllables embedded in a sentence and they received immediate feedback. The pretest to posttest improvement of the slow-only (8.2%) and slow-fast (8.7%) training groups was significantly greater than the control group’s improvement (3.9%). However, the fast-only (7.7%) training group’s improvement did not significantly differ from the control group’s improvement. In addition, slow-fast training, unlike other training, had an advantage in performance on the fast rate stimuli. Implications for the variability theory will be discussed. [ Work supported by NSF Grant No. BCS0418246.]