Sign language
Sign languages have always existed in deaf communities. In ancient texts we see authors commenting about deaf people and sign language. In the western world, the first studies dedicated to sign languages date from the 17th century. In 1620, in Spain, the priest Juan Pablo Bonnet published a text about teaching deaf people to speak, using gestures as a tool. The language of signs created by Bonet was used by Abbé Charles-Michel de l'Épée, to create a fingerspelling alphabet in the 18th century. This alphabet has changed very little since then, and is used with sign languages in many countries.