What they did was:
* Bring French Sign Language (LSF) to America: Clerc, a deaf educator from France, traveled to America in 1816 to teach Gallaudet, a hearing minister, about LSF.
* Establish the first school for the deaf in America: Together they founded the American Asylum for the Deaf (now the American School for the Deaf) in Hartford, Connecticut.
* Develop American Sign Language (ASL): They didn't "invent" ASL, but they played a crucial role in its development. LSF, brought to America by Clerc, became the foundation for ASL, which evolved over time through the interaction and innovations of deaf students and educators.
Therefore, Clerc and Gallaudet didn't invent sign language. Instead, they introduced French Sign Language to America and helped establish the foundations for American Sign Language. Their work revolutionized the education of deaf individuals in America and contributed to the development of a distinct American sign language.