Well, foreign to me. It just so happens that I'm surrounded by native French speakers, and so I'm learning to communicate in French at the moment. Feel free to drop me an email in French and I'll reply in the same!
I'm using wordreference.com as my online dictionary, specifically the French-English section. It does all the major European languages. Yourdictionary.com is also a good portal for multi-lingual dictionaries. I also found a page that describes Accents, Diacriticals and Special Language Characters for Foreign Languages.
I did try learning Spanish to build a very simple Spanish-English translator in Prolog (reaching new heights in buggy software...) for a class assignment. I'm too embarassed to give you my translator, so you'll have to learn the language for yourself. Both these sources are good, but I especially like the first one.
If you want more lessons in languages try Foreign Languages for Travelers.
Being the jack of all trades I am, I also did try Japanese for a while. I didn't get very far, but here are the online resources I used:
My Chinese is equally embarassing at the moment. I haven't done anything in Chinese recently, but I did use this English-Chinese Online Dictionary. For Chinese and other Asian languages, you'll need to download the proper fonts, if you haven't installed your computer in the last 2 years. To edit documents in Chinese or any other Asian language, I recommend the NJStar editor.