Short answers, pulled from the story.
Saka, also called Sakan, is a Middle Iranian language within the Eastern Iranian branch. It is attested through two closely related dialects, Khotanese and Tumshuqese, spoken in the ancient Buddhist kingdoms of Khotan, Kashgar and Tumshuq in the Tarim Basin, in what is now southern Xinjiang, China.
Saka was spoken in the Tarim Basin, in what is now southern Xinjiang, China, centered on the ancient Buddhist kingdoms of Khotan, Kashgar and Tumshuq. Documents survive on wood and paper written in a modified Brahmi script, dating from the fourth to the eleventh century.
In its own documents, Saka was called Hvatanai, the source of the modern name Khotan. The name links the language directly to the kingdom where most of its surviving texts were written.
Saka became extinct after invading Turkic Muslims conquered the Kingdom of Khotan, part of the Islamicisation and Turkicisation of Xinjiang. By the end of the eleventh century the Tarim Basin is believed to have become linguistically Turkified, though Mahmud al-Kashgari still noted in the eleventh century that the people of Khotan kept their own language and script.
Khotanese is attested in more than 2,300 texts preserved among the Dunhuang manuscripts, while Tumshuqese survives in only 15. Harold Walter Bailey deciphered these documents, most of which are religious material connected to the Kingdom of Khotan's Buddhist viharas.
The Saka rulers of the western regions of the Indian subcontinent, the Indo-Scythians and Western Satraps, were traditionally assumed to speak practically the same language as Khotanese and Tumshuqese. More recent research has questioned that assumption.