Do speakers converge rhythmically? A study on segmental timing properties of Grison and Zurich German before and after dialogical interactions

This paper reports on the results of a research investigating whether rhythmic features, in terms of segmental timing properties, are object of speaker’s adjustments after the exposure to a conversational partner. In the context of dialects in contact, this is crucial to understand whether rhythmic attributes may bring about language variation and change. In the context of human-machine interactions, this can benefit the design of spoken dialogues systems to achieve human-likeness. To study rhythmic accommodation, we selected a corpus of pre- and post-dialogue recordings, performed by 18 speakers of Grison and Zurich German (henceforth GRG and ZHG), two Swiss German dialects characterised by noticeable segmental and supra-segmental differences. To quantify rhythmic convergence, we designed three measures based on the segmental timing differences between the two dialects. We compared the Euclidean distances in the three measures between GRG and ZHG speakers in a pair before and after two interactions. Results reveal that dyads members do not significantly shift the production of segmental timing features after the dialogues. Neither linguistic nor social factors can account for the observed accommodation pattern. Cross-dialectal segmental timing differences, captured by the three ratio measures, may be either robust against the influence of interlocutors’ acoustic behaviour or too subtle to be perceived or retained after interactions.