Here's how to change language of Deus Ex Mankind Divided : A Criminal Past Game to English:
Follow these steps below to change it:
To Change the game language:
1. change it in “steam_api64.ini” (Find it in the game folder)
2. run the game
3. select your language in options > language
4. choose English!
Hope it works! If not please ask it on gameslopedy.com