You can select among English, Dutch, French, and German in your Loyaltylion settings.
You can also customise any text appearing in the program which means you can theoretically translate it in any language you want. (we've had customers putting everything in Chinese for example)
However, you can only have one language in use per store. If you have multiple stores you can link them under a unique LoyaltyLion account and choose a different language for each.