Until recently I had multilingual typing enabled on my keyboard. It was possible to swipe in German and English at the same keyboard without changing languages. The spacebar had "English - German" written on it.
Somehow it got accidentally turned off. Maybe by some gesture on the spacebar?
Now I can't figure out how to turn that feature on again. The toggle used to turn it on in the keyboard settings is disabled and can't be turned on.
The hint says that multiple languages have to be enabled. But where can that be done?
On the languages screen there are already two languages. Unfortunately they are also separate keyboards and I always have to switch with the globe button.