Twitter will soon be available in French, Italian, German, and Spanish. This will bring the grand total of languages to six. Twitter is already available in English and Japanese. Of course, that hasn't really stopped people from around the world from Tweeting in everything from Russian to Portuguese - and, of course, Persian.
To assist in adding the new languages, Twitter is seeking volunteers (which borders on crazy if you know how much money they've raised. But hey, even mega-wealthy Google gets people to voluntarily translate for them).
The volunteers will be able to make suggestions to Twitter about translations on the website. Twitter is hoping this will facilitate the quick roll-out of the four upcoming langauges.