First Language Acquisition from a Multimodal Perspective: Insights from Speech, Gesture, and Sign

Children across the world acquire language naturally, regardless of its typology or modality (e.g., signed or spoken) they are born into. Various attempts have been made to explain the language acquisition puzzle using several approaches, trying to understand to what extent it can be explained by what children bring to the language learning situations as well as what they learn from the input and the interactive context. However, most of these approaches consider only speech development, thus undermining the intrinsically multimodal nature of human language. Not only do children have the capacity to learn spoken and/or sign language equally easily but spoken language acquisition also consists of using both modalities, that is, speech and gesture. Thus, language acquisition always involves visual modality, the specifics of which need to be integrated into general theories of language acquisition. This paper aims to synthesize findings from literature focusing on language acquisition with a multimodal perspective in different sign and spoken languages. Our review shows that while some aspects of language acquisition seem to be modality-independent, others might show that acquisition patterns might differ considering the affordances of each modality (either in sign, speech, or gesture). As more and more a multimodal view of language is adopted for the study of adult language (e.g., Kita & Emmorey, 2023; Özyürek & Woll, 2019; Vigliocco et al., 2014), a multimodal approach to language acquisition is inevitable (e.g., Voltera et al., 2017). We discuss whether and to what extent our knowledge of certain aspects of first language acquisition should be reevaluated considering accumulating evidence about the vital role of visible bodily actions and multimodal cues. We also point out which areas need future research for both spoken and sign language acquisition from a multimodal perspective by also taking cross-linguistic variation into account.