Around seven Tanzanian sign languages were independently developed among deaf students in separate Tanzanian schools for the deaf, starting in 1963. However, the use of several is forbidden by their respective schools. In 1984, a standardized Tanzanian Sign Language was proposed by the Tanzania Association for the Deaf, using common or similar signs where these exist in schools that allowed research. However, it has not been officially implemented, and there remains little influence between the languages. A dictionary has been produced, while still several online resources, e.g. SignWiki, PDFs or YouTube videos, are published by different entities.