Untitled

Abstract

Background. High talker variability (i.e. multiple voices in the input) has been found effective in training non-native phonetic contrasts in adults. A small number of studies suggest that children also benefit from high-variability phonetic training with some evidence that they show greater learning (more plasticity) than adults given matched input, although results are mixed. However no study has directly compared the effectiveness of high versus low talker variability in children. Methods. Native Greek speaking 8-year-olds (N=52), and adults (N=41) were exposed to the English /i/-/ɪ/ contrast in ten training sessions through a computerized word learning game. Pre-and posttraining tests examined discrimination of the contrast as well as lexical learning. Participants were randomly assigned to high (4 talkers) or low (1 talker) variability training conditions. Results. Both age groups improved during training, and both improved more while trained with a single talker. Results of a 3-interval oddity discrimination test did not show the predicted benefit of high-variability in training in either age group. Instead, children showed an effect in the reverse direction-i.e. reliably greater improvements in discrimination following single talker training, even for untrained generalization items, although the result is qualified by (accidental) differences in participant groups at pre-test. Adults showed a numeric advantage for high-variability but were inconsistent with respect to voice and word novelty. In addition, no effect of variability was found for lexical learning. There was no evidence of greater plasticity for phonetic learning in child learners. Discussion. This paper adds to the handful of studies demonstrating that, like adults, child learners can improve their discrimination of a phonetic contrast via computerized training. There was no evidence of a benefit of training with multiple talkers, either for discrimination or word learning. The results also do not support the findings of greater plasticity in child learning found in a previous paper (Giannakopoulou et al., 2013a). We discuss these results in terms of various differences between training and test tasks used in the current work compared with previous literature.