Niya Prakrit or Niya Gāndhārī is a Middle Indian language from the 3rd and 4th centuries CE. Having its origins in Northern Pakistan, it came to the southern oases of the Tarim Basin in present-day North-West China, where it was the administrative language of the Shànshàn kingdom, a short-lived state on the Silk Road. The language is named after the archaeological site Niya in the Shànshàn area, where over 750 documents were found, written in the Niya Prakrit language and in the Kharoshthī script.Although obviously of Indian origin, Niya Prakrit also shows influences of its new Central Asian homeland. Spelling mistakes as well as many non-Indian words and numerous foreign names even justify the conclusion that the Shànshàn people had a different mother tongue, which as a substrate language influenced Niya Prakrit in its pronunciation, in the grammar, and in the lexicon.In 1935 Thomas Burrow set up the hypothesis that the substrate language that influenced Niya Prakrit was a form of Tocharian. Two varieties of Tocharian are known so far: Tocharian A and Tocharian B, attested from the 5th century CE in the north of the Tarim Basin. Although a Tocharian substrate as an explanation of the peculiarities of Niya Prakrit is plausible in itself, most of Burrow’s word and grammar comparisons are too vague for definitive conclusions, which is due in particular to the fact that Tocharian was still poorly investigated at the time.The enormous progress made in Tocharian studies since the 1930’s requires a re-evaluation of Burrow’s theory. Should it be confirmed, then this would have important consequences for Tocharian studies, as Tocharian would have been spoken not only in the north of the Tarim Basin, but also in the south. At the same time it would also be an essential contribution to our understanding of the Shànshàn culture and its role in the spread of Indian culture, as well as to our concept of the history of the whole Tarim Basin.