1.Go to your library, right click on Overwatch and select "Properties...".
2.After that select from drop down menu language you want to hear in-game.
To set text language add this line to launch options:
--tank_Locale *language code*
- English: --tank_Locale EnUS
- German: --tank_Locale DeDE
- French: --tank_Locale FrFR
- Japanese: --tank_Locale JaJP
- Russian: --tank_Locale RuRU
- Spanish - Latin America: --tank_Locale esMX
- Portuguese - Brazil:--tank_Locale ptBR
- Polish: --tank_Locale PlPL
- Italian: --tank_Locale ItIT
- Korean: --tank_Locale KoKR
Simplified Chinese: --tank_Locale ZhCN
Traditional Chinese: --tank_Locale ZhTW