english is actually extremely similar to norwegian/swedish/danish (they're basically dialects of the same language). we learn it easily, the odd changes in pronunciation aren't much weirder than what we find between our own different dialect. syntax is also very similar, so similar in fact that scandinavians often make mistakes that mean something in english, just not what they meant to say. we also have a long history of never dubbing movies, so we're exposed to english even before we're born.
i never studied really studied english after grade school. learning came through reading, hearing, speaking, and writing. because i like to read, i ended up getting ahead of most kids, and was a little shocked to learn that 9th graders in a different school couldn't understand texts from the old testament. i had too good teachers at the former school, and tolkien taught me a lot too. i've always been a fan of correct spelling too, that also helps a lot. though i find myself making a bit too many typos when i don't pay attention, or when i switch between norwegian and english keyboard layouts... it could also be mentioned that i studied (general) linguistics in university. half of the students were from africa, so we naturally ended up speaking more english than norwegian.
i also speak both norwegian and lule saami on a daily basis. switching language comes perfectly naturally, some times i switch language from person to person. other times, i'll be in a conversation where all participants switch languages seemingly randomly and often mid sentence. bilingualism is really fun when there's a whole community that have it in common.
(do you have any other interests to pull me off topic with...?)