The Tibetan 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.
For political reasons, the dialects of U-Tsang otherwise known as central Tibet (including Lhasa), Khams, and Amdo are considered dialects of a single Tibetan language, while Dzongkha, Sikkimese, Sherpa, and Ladakhi are generally considered to be separate languages, although their speakers may consider themselves to be ethnically Tibetan. However, this does not reflect linguistic reality: Dzongkha and Sherpa, for example, are closer to Lhasa Tibetan than Khams or Amdo are.
The Tibetan languages are spoken by approximately 6 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. Lhasa Tibetan is spoken by approximately 150,000 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 Khams Tibetan have developed tone. (Amdo and Ladakhi/Balti are without tone.) Tibetan morphology can generally be described as agglutinative, although Classical Tibetan was largely analytic.