It currently supports almost 100 languages. Overall, Google Input Tools is perfect for polyglots, and especially those that work and use the web often in more than one language. It's intelligent in that it saves custom words to your dictionary, perfect to usage of uncommon words and proper names. The application itself doesn't require Windows to install multiple languages or keyboard layouts and instead allows you to quickly swap your key layout or language.
Google Input Tools is a free application which allows you to quickly and easily switch between typing multiple languages.