Short (and only) answer: No, you cannot rent or buy movies in other languages. I share the same problem in Spain, movies are dubbed in spanish.
Matrix sounds hilarious in spanish, trust me.
There's no way to change that. The only solution is -like you've said- switch to the US Store, but that requires billing address changes and all the hurdles involved in that.
I had this exact same issue, and user Tom Gewecke's advice seems to have fixed it for me. I simply removed two plist files in ~/Library/Preferences, and then rebooted. The files were com.apple.CharacterPicker.plist and com.apple.CharacterPaletteIM.plist. I don't know which of those files had the issue, but after removing them and rebooting they've regenerated, and everything's good again.
If you're comfortable with Terminal
You probably know how to move files around, just move these two somewhere else, or rename them:
~/Library/Preferences/com.apple.CharacterPaletteIM.plist~/Library/Preferences/com.apple.CharacterPicker.plist
If you just want something you can copy and paste, here you go:
mv ~/Library/Preferences/com.apple.CharacterPaletteIM.plist{,-backup}
mv ~/Library/Preferences/com.apple.CharacterPicker.plist{,-backup}
Reboot after this, and fingers crossed, it will work for you again.
If you're not so comfortable with Terminal
Open up a Finder window and press Shift ⌘ G (Shift Command G), then type ~/Library/Preferences/, and press Enter. There will be many files in that folder, you're looking for the ones called com.apple.CharacterPaletteIM.plist and com.apple.CharacterPicker.plist. When you find them, you can probably just remove them, but it's always a good idea to back them up. Just move them to another folder or something.
When you've done that, reboot your computer, and see if the Special Characters window works again.
Best Answer
A similar case to what you are experiencing can be found here:
https://discussions.apple.com/thread/3303287?start=0&tstart=0
Pretty weird stuff, but apart from restarting the computer you can try purchasing a free app (I assume through iTunes on the computer), another suggestion that I have read resolved this was to unplug the iPhone and do a reset (hold down the home and lock buttons until the apple logo appears) and then plug it back in when prompted.