Christianity is the largest religion in Tanzania, but there are also substantial Muslim and Animist minorities. Over 100 different languages are spoken in Tanzania, making it the most linguistically diverse country in East Africa. The country does not have a ''de jure'' official language, although the national language is Swahili. Swahili is used in parliamentary debate, in the lower courts, and as a medium of instruction in primary school. English is used in foreign trade, in diplomacy, in higher courts, and as a medium of instruction in secondary and higher education; although the Tanzanian government is planning to discontinue English as the primary language of instruction, it will be available as an optional course. Approximately 10 per cent of Tanzanians speak Swahili as a first language, and up to 90 per cent speak it as a second language.