Ann, like I said, it all comes down to the frequency with which you use a keyboard for one language to type another language. I, for example, spend hours each day writing in multiple languages. ALT key codes would slow my words per minute down to an unacceptable level for me. Besides, when I type, I don't want to think about how to make a letter. I just want to push a button on my keyboard and have it appear on my screen, same as it works when I type in English.
I know that MS Office is localized, but I wasn't aware of an international edition. Anyway, this is a problem that's better addressed at the OS level and not in an application sitting on top of the OS. My two cents.