American Sign Language has a long history in the United States. It goes back almost 200 years, to 1817, when a minister named Thomas Hopkins Gallaudet brought Laurent Clerc, a teacher of the Deaf* (who was also Deaf himself) from France to the United States to found the American School for the Deaf in Hartford, Connecticut.
Clerc brought French Sign Language, which had been developing at schools for the Deaf there since the 1760s, and in Hartford it mingled with various home signs the students brought with them, as well as the sign language of Martha's Vineyard (where there was a high proportion of genetic deafness). Within a matter of decades, ASL had evolved into a rich, full language, capable of handling all the educational and social needs of students at a network of Deaf schools all over the country.
The situation for ASL changed in 1880, when the International Congress on Education of the Deaf resolved that speech training and lip reading were to be the new, preferred method of education. Most deaf schools switched to the oral method, though there was some resistance at schools in the United States. Even at oral schools where signing was forbidden, students continued to use it among themselves and in this way it was passed, surreptitiously and often under threat of punishment, from generation to generation.
By 1913, sign language had been pushed so effectively out of the realm of education that the Deaf community feared for its survival. They decided to take advantage of a new technology, motion pictures, to do what they could to preserve it for posterity. In the film Preservation of the Sign Language (above), George Veditz, teacher and former president of the National Association of the Deaf, stresses the importance of documenting "our beautiful language of signs" as much as possible for the benefit of Deaf people around the world, and claims that "50 years from now these motion pictures will be priceless."
He was right about that. The films made during this time have been invaluable in helping researchers understand how ASL has changed over time. For example, at 3:37 he makes the sign for "jealous" with the tip of his finger between his teeth. It is now produced at the corner of the mouth. Many signs, over time, have moved from a more central to a more peripheral location on the body.
The films have also been invaluable in establishing a place of pride for ASL in American history. The Library of Congress put Preservation in its National Film Registry, a list of "works of enduring importance to American culture," reflecting "who we are as a people and a nation."
Over the last few decades ASL has slowly regained the status it had once enjoyed in the world of education. In 2010, 130 years after the resolution that cast signing out of the schools, the 21st International Congress on Education of the Deaf officially repudiated that resolution and acknowledged the harm it had done. Sign language had survived and flourished despite it all.
See a translation of Veditz's speech here.
*The capital D in Deaf signifies a cultural identity, rather than just a condition of hearing loss.