A.a famous scholar in the study of the human brain
B.a leading specialist in the study of liberal arts
C.an English teacher in a university for the deaf
D.some senior experts in American Sign Language
A.a Substandard language
B.a genuine language
C.an artificial language
D.an international language
A.sign language was not extensively used even by deaf people
B.sign language was too artificial to be widely accepted
C.a language should be easy to use and understand
D.a language could only exist in the form of speech sounds
A.sign language is as efficient as any other language
B.sign language is derived from natural language
C.language is a system of meaningful codes
D.language is a product of the brain