American Sign Language is a visually perceived language based on a naturally evolved system of articulated hand gestures and their placement relative to the body, along with non-manual markers such as facial expressions, head movements, shoulder raises, mouth morphemes, and movements of the body.
American Sign Language (ASL) is a natural language that serves as the predominant sign language of Deaf communities in the United States of America and most of Anglophone Canada. ASL is a complete and organized visual language that is expressed by employing both manual and nonmanual features. Besides North America, dialects of ASL and ASL-based creoles are used in many countries around the world, including much of West Africa and parts of Southeast Asia. ASL is also widely learned as a second language, serving as a lingua franca. ASL is most closely related to French Sign Language (LSF).
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“ASL is a visually perceived, gesture-based language.” That means it is a language that is expressed through the hands and face and is perceived through the eyes. It isn’t just waving your hands in the air. If you furrow your eyebrows, tilt your head, glance in a certain direction, twist your body a certain way, puff your cheek, or any number of other “inflections” –you are adding or changing meaning in ASL. A “visual gestural” language carries just as much information as an oral/aural (mouth/ear) language.
Is ASL limited to just the United States and Canada?
No. ASL is also used in varying degrees in the Philippines, Ghana, Nigeria, Chad, Burkina Faso, Gabon, Zaire, Central African Republic, Cote d’Ivoire, Mauritania, Kenya, Madagascar, Benin, Togo, Zimbabwe, Singapore, Hong Kong and many other places. (Source: Grimes, Barbara F. (editor), (1996). “Languages of USA” Ethnologue: Languages of the World, 13th Edition. Institute of Linguistics.)
Is ASL a universal language?
Nope. Not even close. Those countries I just mentioned also have their own signed languages. ASL is the dominant signed language in North America, plus it is used to some extent in quite a few other countries, but it is certainly not understood by Deaf people everywhere.
(“American Sign Language” 2023), formatting mine