linguistic:voice_change, stylistic:style_transfer
Voiceless velar fricative

Assamese is unusual among Eastern Indo-Aryan languages for the presence of /x/ (realised as or, depending on the speaker and speech register), due historically to the MIA sibilants' lenition to /x/ (initially) and /h/ (non-initially). The use of the voiceless velar fricative is heavy in the eastern Assamese dialects and decreases progressively to the west—from Kamrupi to eastern Goalparia, and disappears completely in western Goalpariya. The change of /s/ to /h/ and then to /x/ has been attributed to Tibeto-Burman influence by Suniti Kumar Chatterjee.