Is nonverbal behavior during conversation related to perceived fluency?

1 INTRODUCTION

Second language (L2) students typically aim to be effective language users, which involves learning both verbal and nonverbal aspects of communication. One aspect of effective language use is fluency, which Segalowitz (2010) described in three ways. The first is cognitive fluency, which is efficiency in a speaker's operation of underlying production processes, for example, at the level of planning, monitoring, and executing an utterance. The second is utterance fluency, which refers to the observable speech features produced by a speaker, such as their pauses or repetitions. Finally, defined as “a judgment made about speakers based on impressions drawn from their speech” (Segalowitz, 2010, p. 48), perceived fluency concerns how a speaker's speech, such as its fluidity or smoothness, impacts the listener. Our focus is on perceived fluency and its previously underexplored link with L2 speakers' nonverbal behavior.

When it comes to observable dimensions of L2 performance that contribute to a speaker's perceived fluency, listeners tend to primarily rely on temporal dimensions of speech such as articulation rate, pausing, and repair in the form of repetitions and self-corrections (Bosker et al., 2013; Kahng, 2018; Saito et al., 2018; Williams & Korko, 2019). Other linguistic dimensions that underpin perceived fluency include grammar and pronunciation, where speakers' morphological and syllable structure errors are associated with lower perceived fluency for listeners (Rossiter, 2009; Suzuki & Kormos, 2020). In terms of the relative weight of various speech characteristics, according to a recent meta-analysis (Suzuki et al., 2021) listeners most strongly associate perceived fluency with articulation speed and pause frequency as opposed to other linguistic dimensions. Considering that up to 60% of variance in perceived fluency in Suzuki et al.'s extensive metadata was unexplained through measures of speaking speed, pausing, and repair, both L2 students and their teachers might find it useful to know which other aspects of communication are tied to perceived fluency, making a speaker appear more or less fluent to listeners.

Considering the tight coordination between speech and various body signals in the form of gesture, torso movement, and eye gaze (Holler, 2022), a speaker's perceived fluency might be associated with various nonverbal behaviors. For example, a speaker might use a round movement of a forearm with an index finger pointing downward when searching for and retrieving a lexical item to describe a cake (Kendon, 1980). In this case, the speaker's reliance on gesture for word retrieval might be a sign of word-finding difficulty (Krauss et al., 2000), which would translate into observable dysfluency phenomena, including hesitations and pauses, all contributing to a decrease in perceived fluency. Alternatively, speakers use various gestures (e.g., hand, head, shoulder, eyebrow, or finger movements) to demarcate the beginnings and ends of meaningful informational chunks or phrase groups in their speech (Kita, 2000). These behaviors might simplify speech segmentation for listeners and emphasize particularly important content (Drijvers & Özyürek, 2017, 2020; Hardison, 2018), with a positive impact on perceived fluency. According to yet another perspective, the visual information available through facial expressions (e.g., smiling, frowning) and gestures might evoke visuospatial imagery for observers, and this additional detail may increase perceived quality of a speaker's speech (Freedman, 1977), including perceived fluency. Put simply, speakers' use of nonverbal behaviors may be associated with how listeners perceive their fluency.

Given that there are no studies known to us that investigate the relationship between nonverbal behavior and perceived fluency, we conducted an exploratory, corpus-based study targeting this issue. Because nonverbal behaviors occur most naturally in interaction rather than in monologic performances, we specifically explored this relationship in L2 conversations. In addition, rather than ask external raters such as teachers, naïve listeners, or trained assessors to provide perceived fluency ratings, we asked the conversational partners to evaluate each other's perceived fluency, assuming that interlocutor perceptions of each other's fluency can impact their interaction. Our study was guided by the following exploratory question: Is there a relationship between the frequency and type of L2 speakers' nonverbal behaviors and their perceived fluency, as evaluated by their interaction partner?