Sign languages can help reveal hidden aspects of the logical structure of spoken language, but they also highlight its limitations because speech lacks the rich iconic resources that sign language uses on top of its sophisticated grammar.
The study, published in Theoretical Linguistics with nine peer-commentaries, is the culmination of more than eight years of research on French Sign Language and American Sign Language (ASL) by Philippe Schlenker, a senior researcher at Institut Jean-Nicod within France's National Center for Scientific Research (CNRS) and a Global Distinguished Professor at New York University.
Sign languages are considered by linguists as full-fledged and grammatically very sophisticated languages, which are essential to the communication of Deaf people. But they also have unique insights to offer on how meaning works in language in general. In several cases, they make visible a logical structure that must be inferred indirectly in spoken language.