It appears when you register from Belgium, the newsletter is sent in French even if you choose Dutch when registering your account.
Belgium is not a bilingual country, it is two unilingual regions that rub together at the edge causing earthquakes. There are definitely people who could take this the wrong way.
Accurately sending the correct language version depending on geographical location can be tricky due to border conflicts, but if the user picks one or the other (or the third: German) it should with that language.
Thanks for your consideration.