Where does “Lít-va” come from?

Lít-va (Vietnamese) comes from Russian Литва́, from Old East Slavic литъва, from Lithuanian Lietuvà, from Proto-Slavic Lētuvā.

Ancestry of “Lít-va”, step by step

StepLanguageWordMeaning
1RussianЛитва́Baltic tribes around the Neman and Daugava river basins, predecessors of modern Lithuanians
2Old East SlavicлитъваAukštaitians; Lithuanians
3LithuanianLietuvàLithuania
4Proto-SlavicLētuvā—
Every word from Proto-Slavic Lētuvā →Every word from Lithuanian Lietuvà →Every word from Old East Slavic литъва →