We've added support for many more languages. See the full list below. You can access the beta by clicking this special link. This link will allow you to use the site, same as before, but will also enable the new language support.
You can find additional supported languages in the footer menu. Once you select your desired language, you can begin creating themes. Try it out and let us know how it works for you. We look forward to reading your feedback and seeing new localized themes in Kuler!