How do I use spell check in OSX with several languages?
Go to system preferences/keyboard/text/spelling and click on the window and go to the Setup item. Then check the boxes for only the two languages you want and set it to Automatic. Also set the dictionary to Automatic in Edit > Spelling and Grammar > Show Spelling and Grammar.
I suspect this works better for separate sentences or paragraphs in different languages than for different languages in one sentence.
Try this:
- Go into System Preferences / Language and Region and set French as Primary language under Preferred languages.
- Restart the computer.
- Set back you previous primary language (by dragging it from the Preferred languages list to the top).
- Restart.
I just tried this, and even after deleting French from my Preferred languages it kept correctly correcting French words.
I'm not entirely sure why, but it seem to do the trick.