Recent research has shown that speakers are sensitive to non-contrastive phonetic detail present in nonnative speech (e.g. Escudero et al. 2012; Wilson et al. 2014). Difficulties in interpreting and implementing unfamiliar phonetic variation can lead nonnative speakers to modify second language forms by vowel epenthesis and other changes. These…

Adults tend to perceive speech sounds from their native language as members of distinct and stable categories; however, they fail to perceive differences between many non-native speech sounds without a great deal of training. The present study investigates the effects of categorization training on adults' ability to discriminate non-native…