Do the 90 percent of Dutch and Scandinavians use English as well as native speakers?

Answer 1

My personal experience, from having lived in Holland and Norway, is no. They are generally advanced, often fluent, but they still make occasional grammatical and usage errors. And I don’t think their working vocabulary will be as large as a native speaker of equivalent age and education.

Pronunciation, intonation, and speech rhythms are rarely brought up to the levels of native speakers. In other words, I can usually hear a strong accent when speaking with people from either country. There are always exceptions of course, but this is my overall impression.