'de-Romanize' originates from English, specifically formed from the prefix 'de-' (from Latin 'de', where 'de-' meant 'remove' or 'reverse') combined with 'Romanize' (from 'Roman', ultimately from Latin 'Romanus', referring to the Romans or Latin script).

'Romanize' developed in English from earlier words referring to 'Roman' (Latin 'Romanus' → Old French/Medieval forms meaning 'of Rome' or 'in the Roman/Latin manner') and came to mean 'to render into Roman (Latin) script'; later English usage added the prefix 'de-' to create 'de-Romanize', meaning the reverse operation.

Originally related forms meant 'to make Roman or to render in the Roman/Latin manner'; over time 'Romanize' specifically came to mean convert into Latin script, and 'de-Romanize' evolved to mean reversing that process — restoring the original non-Latin script.