The most easterly Indo-European languages broke a neat theory of the family
Early in the 20th century, explorers in China's Tarim Basin found Buddhist manuscripts in an unknown tongue. It proved to be a lost branch of the Indo-European family, spoken farther east than any other, yet it sounded like the western languages. The name scholars gave it, Tocharian, turned out to be a mistake.
Nineteenth-century linguists split Indo-European into centum languages in the west and satem languages in the east, a division based on how certain consonants developed. Two discoveries wrecked that tidy map: Hittite, a centum language in Anatolia, and Tocharian, the easternmost branch of all, which also turned out to be centum. Scholars now tend to see the satem shift as an innovation that spread through the centre of the ancient speech area while languages on both fringes kept the older sounds.
Aurel Stein's expeditions brought the first fragments to light, and they turned out to record two related but mutually unintelligible languages. Tocharian A, found only in the east around Turfan and Agni, survives only in religious texts and may have been a liturgical language no longer spoken at home. Tocharian B, from Kucha and beyond, appears in everyday documents too. Its earliest surviving manuscripts may go back to the late fourth century AD, so it was written in the same era as Gothic and Classical Armenian. A supposed third language, Tocharian C, has been dismissed by a Leiden dissertation showing its words were Bactrian or misread.
The label came from Emil Sieg and Friedrich Müller in 1907. They linked an Old Turkic word in a Buddhist colophon to the Tocharoi, a people named by the geographer Ptolemy. Those Tocharoi, however, are now known to have spoken Bactrian, an Iranian language, so the name is a misnomer, though it has stuck. The speakers seem to have called themselves arsi and kusi.
Most scholars trace the Tocharians' ancestors to the Afanasievo culture of southern Siberia, around 3300 to 2500 BC, which later migrated south. The languages probably faded after 840, when Uyghurs driven from Mongolia moved into the basin; Uyghur translations of Tocharian texts support this. A trace may survive in Chinese: the word for honey, mi, may come from a Tocharian source related to English mead.
Source: Tocharian languages
