Guidonian hand
In Medieval music, the Guidonian hand was a mnemonic device used to assist singers in learning to sight-sing. Some form of the device may have been used by Guido of Arezzo, a medieval music theorist who wrote a number of treatises, including one instructing singers in sightreading. The hand occurs in some manuscripts before Guido's time as a tool to find the semitone; it does not have the depicted form until the 12th century. Sigebertus Gemblacensis in 1105–10 did describe Guido using the joints of the hand to aid in teaching his hexachord. The Guidonian hand is closely linked with Guido's new ideas about how to learn music, including the use of hexachords, and the first known Western use of solfege.
Manualism
The first manual schools were in Paris, France. Abbe de l’Épée, a Catholic priest, encountered two teenage deaf girls while visiting a family in the poor part of the city. He decided to take it upon himself to educate them. He invented a technique called "methodical signing" from the signs the girls already used, with the combination of methods influenced by the writings of Johann Konrad Ammann and Juan Pablo Bonet. He created a one-hand manual alphabet to be able to fingerspell French words. L’Épée opened a free national school for the deaf in his home, on 14 Moulins Street (now called Thérèse Street). After his death in 1789, Abbé Roch-Ambroise Cucurron Sicard took over as head of the school; it was renamed Institut National de Jeunes Sourds de Paris. The school received monetary support from individuals and grants from King Louis XVI.