Flemish

Flemish is very like American English (to UK English) in that it’s the Dutch language (of the Netherlands) but a little different.  However, the differences are mainly in how it is spoken, not how it’s written.  So if your localization is written only (not spoken), although a Flemish native will recognise straight way that the translation is either “Flemish” (for Belgium), or “Dutch” (for the Netherlands), no offence would be taken if it’s the latter.  This is because the differences between the written forms of the language are only tiny – things like the written word for “you” is more informal in Dutch than Flemish.  Therefore if budget constraints are tight, you certainly don’t need a Flemish variant (in addition to Dutch) for your written translation.  It’s more of a luxury you might want to afford at a later time.  However as already mentioned, if your project involves audio (not just written text), these language-differences become much more important in spoken Flemish.  If your Flemish project requires voice over, a Flemish variant for Belgium is necessary in addition to the Dutch version for Holland.