Mac OS X: each application has its own input language - how?

Question

macOS

It is necessary to make sure that when switching the language when working with one window, the text input language changes only for it.
I have open:
1) A document in Russian
2) A document in English
And I need to be able to switch windows and write alternately in both documents without switching the language 20 times a minute.

Answer 1

Answer 2

Not what you asked for, but it will solve your problem
superuser.com/questions/718463/how-to-set-the-inpu...