Can a multilingual site be listed multiple times?

My site was originally in Dutch only and is listed in the appropiate category. I added English later. Can a site with more than one language be submitted to multiple categories? It seems the only way to be found by all people speaking one of languages used on the site.

Yes, see http://ch.dmoz.org/guidelines/site-specific.html#multi-lingual <img src="/images/icons/smile.gif" alt="" />

From what you say, your site should be currently listed in a category under World/Nederlands. Go to that category and click on "Engels" under "Deze categorie met sites in andere talen". You will find yourself in the equivalent English language category. Submitting your site there should be enough.

It could be that the really appropriate category is a subcat of that one, because the English language hierarchy of categories is often more developed than the hierarchy of categories in other languages, but don't worry too much over that, the editor who will process your submission should move it if appropriate. Note: it would be probably useful to mention in your submission that the site is now also in English.