 Teaching and research began in 1990 at Tartu University.In 1998 there were about 4,500 signers out of a deaf population of 2000 and a hearing-impaired population ten times that number.It is widespread in the cities of Tallinn and Pärnu among deaf ethnic Estonians; deaf Russians in Tallinn use Russian Sign Language, Russians outside Tallinn tend to use a Russian–Estonian Sign Language pidgin, or may be bilingual.