Option to set or pick a language for spellchecking.

[slizgi]

So right now a spellchecking in the app is based on a language of the system, what is fine as a default settings.
However there should be option to change it I think. Or preferably, have list of spellchecked languages, more than one.
If you have non-English system, then forget about English spellchecking in the app, and vice versa.