If your project includes text or audio in a language outside of those that we currently support (English, German, Japanese, and Spanish), we do ask that you include English translations or subtitles. You're welcome to include translations in other languages as well, however. Kickstarter is a global community, and including translations will definitely help your project have a wider appeal.
Interested in including another language on your project page? Check out our Best Practices for Bilingual Projects.