Investigating the impact of interlocutor voice on syntactic alignment in human–computer dialogue

Language is at the core of most social activity. Psycholinguistic research has shown that our conversational partners influence our linguistic choices be it syntactic or lexical, a concept termed alignment . As our interaction with computer interlocutors become more frequent recent efforts have been made to understand how and what impacts alignment with computers, showing that our perceptions of computer systems impact on alignment with computer interlocutors. This work looks to identify the impact of how spoken dialogue system design characteristics, specifically system voice type, impact user linguistic behaviour in terms of syntactic alignment in human-computer dialogue. Additionally we wished to identify whether syntactic alignment levels can be used as a behavioural indicator of interaction satisfaction. The research used a wizard of oz experiment design paired with a confederate-scripting paradigm commonly used in psycholinguistics research. We found that there was no significant effect of voice type on syntactic alignment, although there was a significant effect of voice type on interaction satisfaction. Participants rated their experiences with a basic computer voice significantly lower in satisfaction compared to human based and advanced voice computer conditions. The results are discussed in terms of the conceptual nature of syntactic alignment and the impact of item stimuli on alignment levels. Future plans for research are also discussed.