You can add more than one language to your registration page. The default language should always be the one you want most participants to use, but you can chose to add translations to all fields in the registration page if you want.
The translations have to be updated manually both under the event settings and under the distance settings. You can add more than one language, but all different languages and fields have to be updated manually, but you can use the "translate with google" service. It's very important that you go through all fields, one by one. If you make any updates in the default language / settings, you have to update also the fields in the translations!