1. French Sign Language (LSF): LSF is widely acknowledged as the most significant influence on ASL. Deaf individuals from France, who had come to America as educators, brought their sign language with them, which was then adopted and adapted by the Deaf community. Many of the basic signs and sign language structures in ASL have roots in LSF.
2. Indigenous Sign Languages: Native American sign languages existed in North America long before European colonization. These languages, while distinct from each other, also contributed to ASL. Some argue that the use of space and facial expressions in ASL, for example, may have been influenced by these Indigenous sign languages.
3. The Deaf Community's Creativity and Adaptation: ASL is a living language, constantly evolving. The Deaf community played a key role in adapting LSF to their own cultural context and needs. They invented new signs, incorporated local vocabulary, and developed a unique system of grammar and syntax. This constant adaptation ensures that ASL remains relevant and dynamic.
It's important to note that the history of ASL is complex and involves the interplay of multiple factors. The sources listed above are major influences, but other factors, like the use of "Martha's Vineyard Sign Language" and the role of educational institutions, also played a part in the development of ASL.