Effects of noise and L2 on the timing of turn taking in conversation

Previous studies of floor-transfer offsets (FTO), the offset from when one talker stops talking to the next one starts, suggest that normal conversation requires interlocutors to predict when each other will finish their turn. We hypothesized that increasing the difficulty of holding a conversation by adding noise and/or speaking in a second language (L2) would result in longer FTOs. Conversations from 20 pairs of normal-hearing (NH), native-Danish talkers were elicited using the Diapix task in four conditions consisting of combinations of language (Danish vs. English) and noise background (quiet vs. ICRA 7 noise presented at 70 dBA). Overall, participants took longer to complete the task in both noise and in L2 indicating that both factors reduced communication efficiency. In contrast to our predictions, in the presence of noise, the median of the FTO distribution decreased by approximately 40 ms and the standard deviation decreased by approximately 60 ms. However, the average median duration of utterances increased by 40% in noise. These findings are consistent with talkers holding their turn for longer, which may allow more time for their own speech planning. Overall, the results suggest that talkers may prioritise maintaining social norms for turn-taking fluency when communicating in difficult environments.