So you want English but the spell check is German, or other way around?
Either way got to Setting and search the word spell. Got to Spell Checker > Languages > then select the language you want. I think that should work but did not try it myself.
Let me clarify. I switch language dozens of times a day. In one chat, I’d write English, in another, I’d write German.
Switching the keyboard language and next word suggestions takes on tap on the globe in the lower right corner.
Switching the spell checking language requires to
Open settings
Navigate to System→Keyboard→Spell checker
Tap “Languages”
Swipe through the long list to find the language I want
Select it
Switch back to the app where I’m actually writing.
I’m looking for some easier way to change the spelling language.
My preferred solution would be if the spelling language were the same as the keyboard language. As it is right now, I cannot use the spell checker at all, because it is
a) too time-consuming to switch the language if I just want to write a quick reply in a chat
b) highly irritating when spell-checking the “wrong” language
The default dictionary is com.android.providers.userdictionary. You describe above selecting a langusge, but is possible to set the uppermost (that is selected) System language. Looking up
Settings > Search: dictionary
one can see modifications one has made by language … including all languages. However, especially rotating keyboard frequently, the dictionary seems out of sync sometimes.
One can import a Multi language dictionary app. Difficult to recommend one, sorry.