Both the Dutch and Swedes (and I guess it goes for Norway and Denmark as well) generally speak English. So much so that my colleagues from other countries find it a problem in that they get very few opportunities to learn Swedish; because everyone just switches to English when they are around.
Yes, I know this effect everywhere. Currently at work in Germany (to be fair: also because it was previously just not practical; I should ask for speaking more german now), or when my girlfriend studied in the Netherlands she said the same. When I was in Finland, people spoke English really really well, but when I looked for an internship, there was not much available in the first place, and that which there was, all required speaking either Swedish or Finnish. (Probably this is better in the capital area, I wasn't near there.) But even if people speak it very well as a secondary language, you're still limited in making friends or finding jobs, even if casual interactions (e.g. stores, school/work friends) try to be helpful and speak english unless you absolutely insist on using your broken version of their language.