Despite various theories about the exact origin of gestures in speech production, researchers generally accept that gesture and speech constitute the product of a single unit of thought within the speaker. On the other hand, what I call gestural mimicry requires consideration
of factors outside such speaker-internal coupling of gesture and speech. Through detailed analysis of a joint narration task and casual conversation in a dyad, I will show that, once perceived and decoded by a partner, the form–meaning relationship of a speaker’s gesture can become
part of the common ground of understanding between the participants. In gestural mimicry, communicativity is observed in the way a speaker’s spontaneous gesture shapes the subsequent gestural move of the interlocutor. With a recurrence of gestural features across speakers, image construal
through gesture becomes an interactional phenomenon. That is, gesture as well as speech provides an interactional resource for co-constructing talk.