The interface in OpenRefine does not have a Dutch language version.
The simplest way to translate OpenRefine is to use Weblate:
The UI strings are grouped into modules that can be translated independently. "Translations" is for the main features, "wikidata" is for the Wikidata-specific ones (from the Wikidata extension), "gdata" is for the Google extension, and so on.
**Take note: we do have a Dutch translation (which is incomplete) - you should be able to find it the language menu as "Nederlands", not "Dutch". It is the second option in the menu, just after "English".**