Optimal variability and perceptual improvement in second language learners

This study investigates the effects of using different levels of stimulus variability during training on the learning of second-language pronunciation. The findings will have implications for the development of language learning tools for learners. Previous research has shown that high variability such as that induced by using different voices help learners develop robust perception of nonnative sound categories. However, previous research has not specified the scope of such variability or the nature of such variability more generally. The knowledge of such a scope may have implications for the location at which a learning tool is the most effective (i.e., “the sweet spot”).