I have added the newest languages offered by Google to the English version of the WordPress Translation Plugin: Afrikaans, Belarusian, Persian, Welsh, Irish, Macedonian, Malay, Swahili or Yiddish.
Because Google is offering a new plugin of its own for any language combination, I think my plugin has become mostly a PHP code to play with, and it will remain so. Their newest Gadget will probably be an excellent tool to offer visitors of any website the possibility to translate with Google, if they don’t have the Google toolbar already installed.
All in all, it’s not a good moment to work on personal plugins that could be replaced in weeks by plugins or gadgets of those big companies, or that could need additions or corrections within weeks. If you want to change or add something to any version of this WordPress Translator Plugin, contact me.
Edit (12 Oct 2009): I’ve added the new language pairs to the German, French, Spanish, Italian, Portuguese and Dutch plugins, which are the most downloaded ones.