ISCA Workshop on Plasticity in Speech Perception (PSP2005)
Senate House, London, UK
The present study investigates how linguistic categories develop in adults and children. Challenging the classical critical period hypothesis, recent research has shown that the adult perceptual system may be more plastic than previously thought. These studies indicate that cortical representations may be continuously shaped throughout life, with accumulating evidence documenting second language learners' ability to perceive and produce non-native contrasts at any age. The present experiments extend this research on the learning of language contrasts by investigating not only what is learned but also how it is learned. Little is known about the acquisition pattern itself, particularly about the shape of the learning curve for new linguistic contrasts and how this affects ultimate attainment.
The present study therefore focused on the learning that occurs during the process of acquisition by assessing learning at different stages in the training regime, examining the step-by-step acquisition of a non-native language contrast. We focused on the suprasegmental tonal contrast (4 Mandarin tones) that has been used productively in our past research (Wang, Spence, Jongman, and Sereno, 1999) and determined the daily gains in accuracy throughout the training procedure for both adults and children.
Six adult native speakers and four elementary school children (ages 6-11) participated. The stimuli were monosyllabic Mandarin words presented in isolation. Five different talkers of Mandarin recorded the stimuli, one talker for the test stimuli (Pretest and Posttests) and 4 talkers for the Training stimuli. The procedure consisted of a Pretest, 6 Training sessions with feedback, and 6 Posttests. Listeners were instructed to indicate which of the four Mandarin tones they heard by pressing one of 4 buttons in front of them.
Overall, adult trainees improved by 19% from Pretest to the final Posttest, very similar to our earlier results showing an overall 21% improvement. Children also did very well, showing a similar improvement (19%) over the 6 training sessions. However, overall accuracy rates were well below those of the adults, with the children only achieving a final 40% correct identification rate while the adults averaged 69% after all training sessions. Differences in the nature of the learning across adults and children were also observed. The present study will evaluate adult-child differences in the acquisition of a novel language contrast and consider the implications for mechanisms involved in learning.
Bibliographic reference. Sereno, Joan / Jongman, Allard (2005): "Language learning in adults and children", In PSP2005, 142 (abstract).