This is a feature common in Windows so far. If you changed language working in some application, this change was limited to that particular application. You could simultaneously write an email in English, edit a Word document in French and fill a web form in Greek. Switching between the three applications would not require manual adjustment of the language.

Now the opposite option too is available. Whatever language you select can become global. If you write an email message in English, you must switch language in Word to write in German, then if you alt+tab again to your email message you have to switch again to English. Some people are pleased with auto language detection, while others are annoyed, but it seems that the majority prefers a globally permanent setting, that won’t change but only manually, since this is now the default Windows option.

Personally I prefer the second way. I’m editing this post now in English, and when I press alt + tab to focus on MS Word, I can immediately type in any language I had previously activated in Word. You can even have two Word documents, editing each of them in a different language, so that switching between these documents won’t require changing manually your language.

To enable language range per application, open Language settings in Control Panel, and go to Advanced Settings. Check there the option “Let me set a different input method for each app window“. This is a rather cryptic description, but it means that you can use two or more languages in various open applications without having to change language whenever you alt tab.