The Tibetic languages are a cluster of mutually unintelligible Tibeto-Burman languages spoken primarily by Tibetan peoples who live across a wide area of eastern Central Asia bordering the Indian subcontinent, including the Tibetan Plateau and the northern Indian subcontinent in Baltistan, Ladakh, Nepal, Sikkim, and Bhutan. The classical written form is a major regional literary language, particularly for its use in Buddhist literature. The Tibetic languages are spoken by approximately 8 million plus people. With the worldwide spread of Tibetan Buddhism, the Tibetan language has spread into the western world and can be found in many Buddhist publications and prayer materials; with some western students learning the language for translation of Tibetan texts. Outside of Lhasa itself, Lhasa Tibetan is spoken by approximately 200,000 exile speakers who have moved from modern-day Tibet to India and other countries. Tibetan is also spoken by groups of ethnic minorities in Tibet who have lived in close proximity to Tibetans for centuries, but nevertheless retain their own languages and cultures. Classical Tibetan was not a tonal language, but some varieties such as Central and Kham Tibetan have developed tone. Amdo and Ladakhi/Balti are without tone. Tibetic morphology can generally be described as agglutinative, although Classical Tibetan was largely analytic.