Speech cues to deception in bilinguals.

Acoustic cues to deception on a picture naming task were analyzed in three groups of English speakers: monolinguals, bilinguals with English as their first language (English-L1), and bilinguals with English as a second language (English-L2). Results revealed that all participants had longer reaction times when generating falsehoods than when producing truths, and that the effect was more robust for English-L2 bilinguals than for the other two groups. Articulation rate was higher for all groups when producing lies. Mean fundamental frequency and intensity cues were not reliable cues to deception, but there was lower variance in both of these parameters when generating false vs. true labels for all participants. Results suggest that naming latency was the only cue to deception that differed by language background. These findings broadly support the cognitive-load theory of deception, suggesting that a combination of producing deceptive speech and using a second language puts an extra load on the speaker.