Sign language does not have an actual creator but instead has evolved over time with influences from different cultures. Many countries have their own versions, just like verbal language has evolved into different dialects depending on the region. While early man was probably the first to use basic signs and gestures to convey meaning, several people have been credited for refining particular versions of their country's signing language.

France:

Juan Pablo de Bonet published the first sign language book in 1620 which contained a manual alphabet system. The pictures of hands in the book formed shapes which represented various speech sounds. De Bonet based his book on the writings of Girolamo Cardano, an Italian physician who invented a code to teach the deaf. Cardano's work had gone unused; however, until De Bonet published his work. Up until then, deaf people were assumed to be slow and incapable of rational thought, but as sign language became popular, the deaf were able to communicate and become functional members of society.

Abbe Charles Michel de L'Epee founded the first free public school in Paris for the deaf in 1755 and taught using a standard sign language he created. L'Epee observed deaf children from all over the country when they came to attend his school, and piecing together their many variations of signing, he created his standard language system using finger-spelling, gestures, and hand signs. L'Epee's standard sign language eventually became the recognized French sign language and is used in France and all over Europe.

America:

American Sign Language is derived from French signing due to a European named Laurent Clerc opening the first American school for the deaf in Hartford, Connecticut in 1817. Clerc taught French signing in Europe and was brought to America by Thomas Hopkins Gallaudet. Together they opened the school, and when children from around the country attended, they brought their own versions of signing. Combining the children's rural variations and Clerc's French signing, the American Sign Language was born.

Some people argue that the large deaf community of Martha's Vineyard in Massachusetts had the greatest influence on American signing. Hereditary deafness became prevalent in the 17th century which caused the community to develop its own brand of sign language. Children from this community then attended Clerc's school and brought this version of signing. The Martha Vineyard's version has been traced to County Kent in the South of England where it was used in woodland areas.

The one unifying theme of all formal sign language development seems to be founding a school and bringing together children from all regions of a country to establish the unified language. However, when deaf children are not taught a formal version of sign language, they will make up their own signs at home with similar patterns and structures to the standard versions.

Venus Kelly is a sales and marketing professional with ten years experience and a degree in business marketing. She writes and maintains Who Invented a website dedicated to Who Invented What http://whoinvented.info/.