Read my tongue movements: bimodal learning to perceive and produce non-native speech /r/ and /l/

This study investigated the effectiveness of Baldi for teaching non-native phonetic contrasts, by comparing instruction illustrating the internal articulatory processes of the oral cavity versus instruction providing just the normal view of the tutor’s face. Eleven Japanese speakers of English as a second language were bimodally trained under both instruction methods to identify and produce American English /r/ and /l/ in a within-subject design. Speech identification and production improved under both training methods although training with a view of the internal articulators did not show an additional benefit. A generalization test showed that this learning transferred to the production of new words.