Hey. I want to add several voice languages to my game, but I do not quite understand how to do it. In wwise it was easy, but how to do it in Fmod, I did not find it.

UP

The only option currently is to embed those different languages into your Fmod Project and make your code call the appropriate event depending on which language the user has setup.

I want to make two separate banks for languages, and put them in the localization pack. In the Flow Graph, I specify which sound I want, but the engine rename the same names. Voice to voice1.

That's exactly what's currently not possible with Fmod Studio.
As a "work around" you will have to create events for each voice line in each language i.e. voice1_english, voice1_russian, voice2_english, voice2_russian and so on and make the game code call the appropriate event depending on the language.