Languages that don't appear to be languages: the discovery of sign languages

Gesture-based communications systems that have been traditionally used by the deaf have been systematically viewed as an invention belonging to deaf people to compensate for their lack of complete access to oral language. Since the middle of the 20th century, however, linguistics has demonstrated that these systems possess all the distinctive properties of natural human languages, with the particularity that they are organised and perceived through gestural-visual channels. This discovery has helped to emancipate signer communities, as well as the progressive reclaiming of their linguistic and civic rights, one very recent example being the passing of the Catalan sign language law by the Parliament of Catalonia.