Effects of Noise and Second Language on Conversational Dynamics in Task Dialogue

This study provides a framework for measuring conversational dynamics between conversational partners (interlocutors). Conversations from 20 pairs of young, normal-hearing, native-Danish talkers were recorded when speaking in both quiet and noise (70 dBA sound pressure level [SPL]) and in Danish and English. Previous studies investigating the intervals from when one talker stops talking to when the next one starts, termed floor-transfer offsets (FTOs), suggest that typical turn-taking requires interlocutors to predict when the current talker will finish their turn. We hypothesized that adding noise and/or speaking in a second language (L2) would increase the communication difficulty and result in longer and more variable FTOs. The median and interquartile range of FTOs increased slightly in noise, and in L2, there was a small increase in interquartile range but a small decrease in the median of FTO durations. It took the participants longer to complete the task in both L2 and noise, indicating increased communication difficulty. The average duration of interpausal units, that is, units of connected speech surrounded by silences of 180 ms or more, increased by 18% in noise and 8% in L2. These findings suggest that talkers held their turn for longer, allowing more time for speech understanding and planning. In L2, participants spoke slower, and in both L2 and noise, they took fewer turns. These changes in behavior may have offset some of the increased difficulty when communicating in noise or L2. We speculate that talkers prioritize the maintenance of turn-taking timing over other speech measures.