Vamp allows the user to select a preferred language for its user interface. The authors are native English speakers, and that is Vamp's default language. We are happy to add support for additional languages if native speakers will provide interface translations.
Without going into technical detail, all of the user interface text that requires translation exists in a single language-specific file. The default (US English) version is here. If you provide us with a translation for your language, we will incorporate it into a future version of Vamp. We'll also work with you on any confusing parts of the interface.