Depending on how high a bar you want to meet, it may be worthwhile to also try with a language farther from English than Dutch is. If I really wanted to be thorough, I might try to take two bilingual people, give one the English and one the non-English, and ask them to discuss the results with one another and/or with you. Or, even better, give it to people who don’t speak English, and don’t know it was translated from English, and therefore can’t subconsciously use knowledge of English to correct translation problems. But for a lot of use cases I agree that these would be unnecessary.
That’s good news!
Depending on how high a bar you want to meet, it may be worthwhile to also try with a language farther from English than Dutch is. If I really wanted to be thorough, I might try to take two bilingual people, give one the English and one the non-English, and ask them to discuss the results with one another and/or with you. Or, even better, give it to people who don’t speak English, and don’t know it was translated from English, and therefore can’t subconsciously use knowledge of English to correct translation problems. But for a lot of use cases I agree that these would be unnecessary.