There is solution but most likely you will not like it.
There is no choice as there is only one language pack at a time installed now using Galaxy after introduction of new download engine. Strangely enough there is no choice in-game to set spoken language to English, although it doesn't have it's language pack as it is built into main game files.
Sliders shows back after you install additional language packs. But you have to switch to manual update, and updating game will mess things up, so you will have to repeat. Switch to manual update and just set game to English and it'll download about 3 gigs of files, then apply language packs for all languages you are going to use. Slider will be there.
Certainly some thing to improve, but it's beta. And as long as there is a way around it I don't care.