If you go for example to 'Inventory' or 'Sales' > 'Configuration' > 'Attributes' you can select the attribute which need translating (e.g., 'colour'). Here you should see a list of all defined colours (e.g., 'black). If you click/edit in this colour you should see a language code. If you click here you can change the translation for the other language (i.e., Dutch in your case).

I hope this helps.