FYI: to fix the keyboard language switching problem, install an additional keyboard, like Hacker's Keyboard, then toggle to the other keyboard when you're doing English typing. Then toggle back to the Samsung one if you're going to type in a foreign language. Then whacking the space bar wont trigger the language switch while you're typing in English.

It seems to be a problem with the Samsung keyboard. Maybe installing a different keyboard that does IME (like google's) would also fix the problem.