Charles-Michel de l'Épée was born to a wealthy family in Versailles, the seat of political power in what was then the most powerful kingdom of Europe. He studied to be a Catholic priest.

L'Épée then turned his attention toward charitable services for the poor, and, on one foray into the slums of Paris, he had a chance encounter with two young deaf sisters who communicated using a sign language. L'Épée decided to dedicate himself to the education and salvation of the deaf, and, in 1760, he founded a school. In line with emerging philosophical thought of the time, the Abbé de l'Épée came to believe that deaf people were capable of language and concluded that they should be able to receive the sacraments and thus avoid going to hell. He began to develop a system of instruction of the French language and religion. In the early 1760s, his shelter became the world's first free school for the deaf, open to the public.

Though L'Épée's original interest was in religious education, his public advocacy and development of a kind of "Signed French" enabled deaf people to legally defend themselves in court for the first time.

L'Épée died at the beginning of the French Revolution in 1789, and his tomb is in the Church of Saint Roch in Paris. Two years after his death, the National Assembly recognised him as a "Benefactor of Humanity" and declared that deaf people had rights according to the Declaration of the Rights of Man and of the Citizen. In 1791, the Institution Nationale des Sourds-Muets à Paris, which L'Épée had founded, began to receive government funding. It was later renamed the Institut St. Jacques and then renamed again to its present name: Institut National de Jeunes Sourds de Paris. His methods of education have spread around the world, and the Abbé de l'Épée is seen today as one of the founding fathers of deaf education.

After L'Épée's death, he was succeeded by the Abbé Roch-Ambroise Cucurron Sicard, who became the new head of the school.

 

The Abbé's signes méthodiques are represented on his funeral monument in the Church of St. Roch, Paris

The Instructional Method of Signs (signes méthodiques)

The Instructional Method of Signs is an educational method that emphasised using gestures or hand signs, based on the principle that "the education of deaf mutes must teach them through the eye of what other people acquire through the ear." He recognised that there was already a signing deaf community in Paris but saw their language (now known as Old French Sign Language) as primitive. Although he advised his (hearing) teachers to learn the signs (lexicon) for use in instructing their deaf students, he did not use their language in the classroom. Instead, he developed an idiosyncratic gestural system using some of this lexicon, combined with other invented signs to represent all the verb endings, articles, prepositions, and auxiliary verbs of the French language.

In English, the Abbé de L'Épée's system has been known as "Methodical Signs" and "Old Signed French" but is perhaps better translated by the phrase systematised signs. While L'Épée's system laid the philosophical groundwork for the later developments of Manually Coded Languages such as Signed English, it differed somewhat in execution. For example, the word croire ("believe") was signed using five separate signs—four with the meanings "know", "feel", "say", and "not see" and one that marked the word as a verb (Lane, 1980:122). The word indéchiffrable ("unintelligible") was also produced with a chain of five signs: interior-understand-possible-adjective-not. However, like Manually Coded Languages, L'Épée's system was cumbersome and unnatural to deaf signers. A deaf pupil of the school (and later teacher), Laurent Clerc, wrote that the deaf never used the signes méthodiques for communication outside the classroom, preferring their own community language (French Sign Language).

Although L'Épée reportedly had great success with this educational method, his successes were questioned by critics who thought his students were aping his gestures rather than understanding the meaning.