With National Science Foundation support, Dr. Yukari Hirata will investigate the perception of second language (L2) vowel length contrasts in sentences produced at various speaking rates. The vowel length distinction (short versus long) is phonemic in Japanese, but is difficult for native English speakers to acquire. A long vowel is by definition longer in duration than a short vowel, but a long vowel spoken quickly can actually be shorter than a short vowel spoken slowly. It is not known how learners of Japanese process such speaking rate variations and learn to distinguish vowel length accurately. Studying the vowel length distinction in a sentence context is particularly important, since previous research has shown that native listeners use sentence rate for making duration-based distinctions, and that they automatically adjust their perception of a segment based on the speaking rate. This study will provide important insights into the ability of "nonnative listeners" to utilize cues from speaking rate in the perceptual learning process. The project will investigate the extent to which three types of perceptual training in the laboratory assist native English speakers in learning to perceive Japanese vowel length distinction: training with a slow speaking rate, training with a fast rate, and training with both slow and fast rates. The hypothesis is that sentences spoken at varied rates (slow and fast) contain more diverse and rich acoustic cues than sentences spoken only at a slow or a fast rate, and that the richer cues will aid nonnative listeners in adjusting speaking rate and in identifying short/long vowels accurately.
This research will increase our understanding of the relationship between speech input and perceptual learning, an important issue for theories of L2 acquisition. The broader impacts of this research are several: First, the research will serve as a foundation on which practical improvement can be made in L2 pedagogy and computer-assisted L2 learning. This project has the potential to significantly improve current methods of language instruction, which is beneficial to society as a whole, given increasing globalization and the attendant need for individuals to be able to communicate effectively across cultures. Second, the project allows for integration of research into the educational experience of undergraduate students, helping to expose them to the excitement of scientific inquiry. Third, the development of the infrastructure for this research at Colgate University will enable undergraduates to participate in additional phonetics studies even when the current project is concluded. Creating an on-campus lab for phonetic research will enrich and diversify science education at an undergraduate institution.
