Add-on for Google Docs that puts a menu of accented characters on the right side of the screen for your chosen language. Click to add accented character.
Learn languages for free online
English, Spanish, French, German, Italian, Japanese, Portuguese, Russian, Polish, Turkish, Arabic, Chinese
Limitations: Content is limited in the free version.
I have found that this site is much better for language augmentation than actual language acquisition. The exercises and topics are useful for adding to what an individual already knows and are useful for brushing up skills.
The ability to test into a level is an added bonus!
Verbix on-line verb conjugator supports verb conjugation in numerous languages: Spanish, French, Italian, Dutch, Danish, and more. Online version of 500 Conjugated Verbs book series (unaffiliated with books).