I’m using Windows 8 system for my regular daily work. I’m using English as the display language and most time I type English since it is the work language in this company. However, I’m a Chinese and it is pretty reasonable that I sometimes need to type Chinese in, for example, the IM message window to chat with my friends. So, of course I have Chinese language and its IMEs installed.
Not like in the previous versions of Windows, win 8 now uses Win+space hotkey to switch between the languages. So the beloved years of Ctrl+space disappears. And, another damn thing I really hate is, once I switch the IME, all running applications now are with that IME. Which means I have to switch again and again between English input and Chinese input always, once after I have to deal with a friend with whom I have to type Chinese.
So today I’m enough with this switch and spent some little more time on the language configurations of win 8 and it turns out I can get my comfortable ways back. 
Use the Change your language preferences windows, open the Advanced settings option, and turn on the Let me set a different input method for each app window option. Then log off and re-login, all the familiar behaviors are back and voilà!