Having a different pointing of view about the future: The effect of signs on co-speech gestures about time in Mandarin–CSL bimodal bilinguals

Mandarin speakers often use gestures to represent time laterally, vertically, and sagittally. Chinese Sign Language (CSL) users also exploit signs for that purpose, and can differ from the gestures of Mandarin speakers in their choices of axes and direction of sagittal movements. The effects of sign language on co-speech gestures about time were investigated by comparing spontaneous temporal gestures of late bimodal bilinguals (Mandarin learners of CSL) and non-signing Mandarin speakers. Spontaneous gestures were elicited via a wordlist definition task. In addition to effects of temporal words on temporal gestures, results showed significant effects of sign. Compared with non-signers, late bimodal bilinguals (1) produced more sagittal but fewer lateral temporal gestures; and (2) exhibited a different temporal orientation of sagittal gestures, as they were more likely to gesture past events to their back. In conclusion, bodily experience of sign language can not only impact the nature of co-speech gestures, but also spatio-motoric thinking and abstract space-time mappings.