Simplify the following text for a Grade 10 native English-speaking person.
Original: American Sign Language , or ASL , for a time also called Ameslan , is the dominant sign language of Deaf Americans , including deaf communities in the United States , in the English-speaking parts of Canada , and in some regions of Mexico .
Simplified: American Sign Language ( old names : Amslan , Ameslan ) is the most popular sign language for the Deaf in the United States , in the English-speaking parts of Canada , and in parts of Mexico .