Humans readily engage in idle chat and heated discussions and negotiate tough joint decisions without ever having to think twice about how to keep the conversation grounded in mutual understanding. However, current attempts at identifying and assessing the conversational devices that make this possible are fragmented across disciplines and investigate single devices within single contexts. We present a comprehensive conceptual framework to investigate conversational devices, their relations, and how they adjust to contextual demands. In two corpus studies, we systematically test the role of three conversational devices: backchannels, repair, and linguistic entrainment. Contrasting affiliative and task-oriented conversations within participants, we find that conversational devices adaptively adjust to the increased need for precision in the latter: We show that low-precision devices such as backchannels are more frequent in affiliative conversations, whereas more costly but higher-precision mechanisms, such as specific repairs, are more frequent in task-oriented conversations. Further, task-oriented conversations involve higher complementarity of contributions in terms of the content and perspective: lower semantic entrainment and less frequent (but richer) lexical and syntactic entrainment. Finally, we show that the observed variations in the use of conversational devices are potentially adaptive: pairs of interlocutors that show stronger linguistic complementarity perform better across the two tasks. By combining motivated comparisons of several conversational contexts and theoretically informed computational analyses of empirical data the present work lays the foundations for a comprehensive conceptual framework for understanding the use of conversational devices in dialogue.

Do people adjust their conversational strategies to the specific contextual demands of a given situation? Prior studies have yielded conflicting results, making it unclear how strategies vary with demands. We combine insights from qualitative and quantitative approaches in a within-participant experimental design involving two different contexts: spontaneously occurring conversations (SOC) and task-oriented conversations (TOC). We systematically assess backchanneling, other-initiated repair and linguistic alignment. We find that SOC exhibit a higher number of backchannels, a reduced and more generic repair format and higher rates of lexical and syntactic alignment. TOC are characterized by a high number of specific repairs and a lower rate of lexical and syntactic alignment. However, when alignment occurs, more linguistic forms are aligned. The findings show that conversational strategies adapt to contextual demands.

Humans readily engage in idle chat, heated discussions, and negotiate tough joint decisions without ever having to think twice about the different mechanisms they use to keep the conversation grounded in mutual understanding. However, current attempts at identifying and assessing the grounding mechanisms that make this possible are fragmented across disciplines and investigate single mechanisms within single contexts. We present a comprehensive conceptual framework to investigate and quantify conversational grounding mechanisms, and how they adjust to contextual demands. In three corpus studies, we systematically test the role of three grounding mechanisms, backchannels, repair, and interactive alignment. Contrasting affiliative (AC) and task-oriented (TOC) conversations between and within participants, we find that grounding mechanisms adaptively adjust to the increased need for precision in the latter: Across Study 1 and Study 2, we show that low-precision mechanisms such as backchannels are more frequent in AC, while more costly but higher-precision mechanisms, such as specific repairs, are more frequent in TOC. Further, TOC involve higher complementarity of contributions in terms of the content and perspective: lower semantic alignment, and less frequent (but richer) lexical and syntactic alignment. Crucially, in Study 3, these variations in the use of grounding mechanisms are shown to be adaptive: pairs of interlocutors that show stronger linguistic complementarity perform better across the two tasks. By combining motivated comparisons of several conversational contexts, and theoretically informed computational analyses of empirical and experimental data, the present work lays the foundations for a comprehensive conceptual framework of grounding mechanisms in conversation.

Establishing and maintaining mutual understanding in everyday conversations is crucial. To do so people employ a variety of conversational devices, such as backchannels, repair and linguistic entrainment. Here we explore whether speakers of different languages use conversational devices in the same way, or whether their use might be modulated by differences in properties of the languages. We compare two unusually well-matched languages (Danish and Norwegian) differing in their sound structure: Danish is more opaque due to, e.g., phonetic reduction in pronunciation. Across systematically manipulated conversational contexts, we find that processes supporting mutual understanding in conversations vary with external constraints: across different contexts, and, crucially, across languages. According to our predictions, linguistic entrainment was overall higher in Danish than Norwegian, while backchannels and repairs presented a more nuanced pattern. These findings suggest that native speakers of Danish compensate for the opaque sound structure by adopting a top-down strategy of building more conversational redundancy through entrainment, which also reduces the need for repairs. By creating a context in which linguistic items and structures are continuously repeated, native speakers of Danish might be bypassing the challenges posed by their pronounced phonetic reduction. These results suggest that linguistic differences might give rise to systematic changes in language processing and use and pave the way for larger cross-linguistic investigations. The findings are highly relevant for the study of conversational exchanges in many applied domains, from the design of language-based human-computer interfaces to the development of measures of social functioning in neuropsychiatric conditions.

The phonological peculiarities of spoken Danish have been argued to reduce the salience of cues that allow infant listeners to extract linguistic information from the speech stream. To assess whether caregivers adjust their infant-directed speech to accommodate these processing challenges, this study compares the acoustic properties of 26 Danish caregivers’ spontaneous speech when interacting with their 11-24-month-old infants (i.e., infant-directed speech, IDS) and when interacting with an adult experimenter (i.e., adult-directed speech, ADS). We compare the two speech styles on both prosodic and vocalic dimensions by extracting 25,577 prosodic measures from utterances as well as 9255 vocalic measures from manually annotated vowel tokens. We construct Bayesian multi-level models of each acoustic feature and critically incorporate statistical information from prior studies into our analyses. The results indicate that Danish IDS conforms to general cross-linguistic patterns in its prosodic properties, with a higher overall pitch, a greater degree of pitch variability and a slower articulation rate. Crucially, though, the acoustic properties of Danish vowels contradict cross-linguistic tendencies: Danish caregivers tend to produce IDS with a reduced or similar vowel space area, higher within-vowel variability, and a lower degree of distinctiveness between vowel categories. We argue that these results beg for future research to pursue theory-driven comparisons of the acoustic expression of IDS across a wide intersection of languages with distinct phonological systems.