Lip-reading and Bilingualism

This study investigated whether observers can identify what language was being spoken in visual-only speech stimuli, and whether or not this ability depends on an observers’ prior linguistic experience. Participants watched visual-only speech stimuli and were asked to decide if the talker in the video was speaking English or Spanish. Four groups of participants were studied: monolinguals and bilinguals, who were either native speakers of English or native speakers of Spanish. Results revealed that all subjects were able to identify the language being spoken with about 80% overall accuracy, regardless of their language background. However, the groups of participants differed in terms of their response bias. The L1 English bilinguals were strongly biased toward their native language, whereas the other three groups of participants did not demonstrate a significant bias toward the L1. The results of this experiment and their implications are discussed, and several directions for future research are considered.