Does sound symbolism need sound?: The role of articulatory movement in detecting iconicity between sound and meaning

Ever since de Saussure [Course in General Lingustics (Columbia University Press, 1916)], theorists of language have assumed that the relation between form and meaning of words is arbitrary. However, recently, a body of empirical research has established that language is embodied and contains iconicity. Sound symbolism, an intrinsic link language users perceive between word sound and properties of referents, is a representative example of iconicity in language and has offered profound insights into theories of language pertaining to language processing, language acquisition, and evolution. However, on what basis people detect iconicity between sound and meaning has not yet been made clear. One way to address this question is to ask whether one needs to be able to hear sound to detect sound symbolism. Here, it is shown that (1) deaf-and-Hard-of-Hearing (DHH) participants, even those with profound hearing loss, could judge the sound symbolic match between shapes and words at the same level of accuracy as hearing participants do; and (2) restriction of articulatory movements negatively affects DHH individuals' judgments. The results provided support for the articulatory theory of sound symbolism and lead to a possibility that linguistic symbols may have emerged through iconic mappings across different sensory modality-in particular, oral gesture and sensory experience of the world in the case of speech.