languagemacos
I tried to change input language by pressing shortcut commandspace and also by choosing language on the menu bar. It automatically switches to English language.
The only way I found to fix it by rebooting the Mac.
Maybe someone knows another way?
I'm using English, Japanese and Russian on a MacBook Pro running OS X Yosemite 10.10.5.
This adds the language selection to the login window:
Could it be that you are accidentally hitting the input source switching shortcuts? If so, you can disable them in the System Preferences.
Also, if you find that the input language changes when you switch apps, this is actually normal behavior. By choosing “Use the same one in all documents” in the input source options, you can greatly decrease the chances of this happening. (With the exception of a few apps that seem to ignore/override this setting. Very annoying.)
If you've experienced this problem only when using Japanese keyboards, then I guess there is a different cause. I use US keyboards, but this unintended switching happens to me too. Mostly when switching to Adobe apps.
Best Answer
By putting Mac to sleep(holding the power button for couple sec) and then log in again it solves the problem, and I'm able to switch languages again.