In the last fifteen years, philosophical interest in inner speech has increased drastically. Although philosophers working on the topic have often made claims about inner speech generally, it seems they have often only been thinking about inner speech in voiced languages. However, inner speech can also take place in sign languages. Externally signed speech differs from externally voiced speech in ways which go beyond the sensory modality involved. For one thing, the experience of externally signed speech is perspective-relative in a way that the experience of externally voiced speech is not. For another, the process of signing externally (moving one’s hands etc.) is not distinct from the speech produced (the movements), whereas the process of producing voiced speech externally (moving one’s mouth) is distinct from the sounds produced (the soundwaves). This justifies the extrapolation that inner speech in sign languages may differ in important ways from inner speech in voiced languages. I show that a number of claims that have been made about inner speech—about the content of inner speech, about the tokening of words in inner speech, and about the role of inner speech in self-knowledge—are complicated if one takes account of inner speech in sign languages.
Daniel Gregory (Wed,) studied this question.