This paper reports linguistic fieldwork and the setting of a psycholinguistic exper-
ment on Japanese Sign Language, the first language of Deaf people. The fieldwork
aimed to investigate sign language with some Deaf linguistic consultants. First, we
examined the linguistic environment around deaf people, which indicates that the age
of acquiring sign language and their bilingual condition should be considered. Sec-
ond, we investigated the matter of social status in which hearing researchers are the
majority who oppress Deaf people as a minority in society. Third, while setting up
a psycholinguistic task to collect linguistic data from several Deaf people, we found
issues that need to be solved, such as their bilingual environment and visual modality
dependence of their communication, and the linguistic elements of sign language. We
found a phenomena that, while looking away, Deaf people say something the addressee
cannot understand, but during eye contact with the addressee, almost all signs are
comprehensible.
