'sung' originates from Old English, specifically the word 'sungen' (the past participle of 'sing'), where the root goes back to Proto-Germanic '*sengwaną' meaning 'to sing'.

'sung' changed from the Old English word 'sungen' (past participle of 'singan') through Middle English 'sungen' and eventually became the modern English form 'sung'.

Initially, the root meant 'to sing' (produce musical sounds with the voice); over time the past-participle form developed its grammatical use as 'having been sung' and as an adjective meaning 'performed vocally'.