We are a highly international camp and we welcome kids of all nationalities. Some kids speak only English, others speak only Dutch, and most of them speak both languages and even more!
The story and all instructions are given in English and Dutch, and while not all the camp counselors speak Dutch, there is always someone around who speaks Dutch. We also speak Spanish, French, some German, and often other languages.
The beauty of kids is that they communicate in other ways and in our experience language is never a problem. As a side benefit, some Dutch kids end up speaking some English at the end of the week! 🙂