American Sign Language Day, observed every April 15, celebrates American Sign Language (ASL), the predominant sign language of Deaf communities in the United States and most of Anglophone Canada. The date commemorates the opening of the American School for the Deaf in 1817, where ASL developed from Old French Sign Language, influenced by various village sign languages. Today, approximately one million people use ASL as their primary means of communication, although 98% of deaf individuals do not receive education in sign language. The day aims to promote the development of ASL within the Deaf community and to encourage hearing individuals, particularly those with deaf relatives, to learn and use sign language. It also serves as a professional holiday for educators, ASL teachers, and interpreters working with ASL.