Having / Switching between two primary languages of Android phones (NOT via the keyboard's language)

[Solal]

(I thought I'd ask here too, so here I go
Hi everyone!
I see around the Internet that I'm not the only one with this problem: I work as a translator, and as such I often speak two languages more or less at the same time in my emails and texts -- or at least I switch between the two (French and English) constantly.
I have a keyboard app that lets me switch from one to the other, and spell-check too. However, if the keyboard works, the phone itself doesn't recognize the language when it's not the one currently set in the phone's settings. Incidentally, everything I type gets underlined red, and each time I reposition my pointer onto a word, a menu opens that allows me ("forces me", rather) to replace my "misspelled" word with a approximate, useless, wrong-language correction of it.
This is really annoying, and most people don't seem to get that downloading a new keyboard with amazing options will not solve the problem, as it is the phone itself that cannot handle two "primary" languages at the same time.

Hasn't anyone got an idea on how to solve this? This slows me down each and every time I need to change language mid-sentence in an e-mail or text message, which is everyday.
I thought that a roundabout way to fix this would be a "Phone's Language Switcher widget" , which would do the trick - although that wouldn't be as simple as just havinge the phone recognize that I speak two languages at the same time.
I haven't been able to find anything resembling that, but if someone has heard of anything that fits the description or that would help me solve this, I'd be really grateful if they would let me know!
Thanks!

Sol

(Edit: The "language/locale switcher" apps on the Play Store only work (if they do) on rooted phones, and mine (ZTE Apex Blade 2) is not rootable as of today, as far as I know. Sooo, that's not possible either...)

 

[Javier P]

I haven't found a solution for that as well. I use three different languages and the keyboard that I found to be the best is SwiftKey. You don't need to switch between languages when you type and prediction is quite good. But, as you said, spell checking is a problem. Everything not written in the language set in your input settings is going to be underlined. And, of course, unchecking auto spell is not exactly an option.

Good luck and please report back if you find a solution. It could be much appreciated.

 

[Javier P]

If you want to change the language in the settings there's a way to make that process quicker. Use Nova launcher and create a shortcut with Activities to go straight to the languages list.