Its usage declined starting in the late ninth century when the Bamar people of Nanzhao began to overtake the Pyu city-states.

[5] Miyake (2021, 2022) argues that Pyu forms a branch of its own within the Sino-Tibetan language phylum due to its divergent phonological and lexical characteristics.

Pyu is not a particularly conservative Sino-Tibetan language, as it displays many phonological and lexical innovations as has lost much of the original Proto-Sino-Tibetan morphology.

[8] Pyu was tentatively classified within the Lolo-Burmese languages by Matisoff and thought to most likely be Luish by Bradley, although Miyake later showed that neither of these hypotheses are plausible.

The Chinese records state that the 35 musicians that accompanied the Pyu embassy to the Tang court in 800–802 played music and sang in the Fàn (梵 "Sanskrit") language.