Research on language development shows that deaf adults who acquired American Sign Language (ASL) in adolescence or adulthood never become as proficient as those who learned it in childhood. This is consistent with the sensitive-period notion.
Explanation:
American Sign Language (ASL) serves as the predominant sign language of Deaf communities in America and most of Anglophone Canada.
The sign languages use visual-manual modality to convey meaning. Sign languages are developed natural languages with their own grammar and lexicon. Facial expressions, hand movements and postures of the body are also used as a part of sign language.
American Sign Language is commonly followed by the deaf people as one of the communication option in America.
