The Tibetan language comprises a wide range of spoken and written varieties whose known history dates from the 7th century AD to the present day. Its speakers inhabit a vast area in Central Asia and the Himalayas extending into seven modern nation states, while its abundant literature includes much of vital importance to the study of Buddhism. After surveying all the known varieties of Tibetan, including their geographical and historical background, this book concentrates on a phonological and grammatical description of the modern spoken Lhasa dialect, the standard spoken variety. The grammatical framework which has been specially devised to describe this variety is then applied to the written varieties of Preclassical and Classical Tibetan, demonstrating the fundamental unity of the language. The writing system is outlined, though all examples and texts are given in roman script and where appropriate, the International Phonetic Alphabet. There is a comprehensive bibliography.