<P> ASL is sometimes incorrectly cited as the third - or fourth-most - spoken language in the United States . These figures misquote Schein and Delk (1974), who actually concluded that ASL speakers constituted the third - largest population requiring an interpreter in court . Although this would make ASL the third-most used language among monolinguals other than English, it does not imply that it is the fourth-most - spoken language in the United States, since speakers of other languages may also speak English . </P> <P> ASL is used throughout Anglo - America . This contrasts with Europe, where a variety of sign languages are used within the same continent . The unique situation of ASL seems to have been caused by the proliferation of ASL through schools influenced by the American School for the Deaf, wherein ASL originated, and the rise of community organizations for the Deaf . </P> <P> Throughout West Africa, ASL - based sign languages are spoken by educated Deaf adults . These languages, imported by boarding schools, are often considered by associations to be the official sign languages of their countries, and are named accordingly, e.g. Nigerian Sign Language, Ghanaian Sign Language . Such signing systems are found in Benin, Burkina Faso, Ivory Coast, Ghana, Liberia, Mauritania, Mali, Nigeria, and Togo . Due to lack of data, it is still an open question how similar these sign languages are to the variety of ASL used in America . </P> <P> In addition to the aforementioned West African countries, ASL is reported to be used as a first language in Barbados, Bolivia, Cambodia, the Central African Republic, Chad, China (Hong Kong), the Democratic Republic of the Congo, Gabon, Jamaica, Kenya, Madagascar, the Philippines, Singapore, and Zimbabwe . ASL is also used as a lingua franca throughout the deaf world, widely learned as a second language . </P>

American sign language is a true and complete language according to linguists