[svandamme]

i spoke fluent english by the age of ten, just by watching english language tv shows
french took a bit longer, didn't pick it up in school, did pick it up party'ing and pulling birds...
These days, i'm accentless in english, or rather, i switch english accents depending on who i'm hanging out with (irish, scottish, northern englanders, american, or even specific american accents, Boston accent, southern accent ... i pick em up in no time flat

When i was 5-10, there hardly were any tv shows for kids in dutch, at least not big productions
So the bulk of what i watched was English language stuff, the A-team, Knight Rider, Airwolf, Battle Star Galactica, Star Trek, rerun's of The avengers or the saint...
subtitled
Movies and cartoons, same thing, Snow white, Jungle book, Donald Duckonly in english, with subtitles

my kid sister, is 9 ... she is not even close to where i was at her age

why, All disney and kids movies these days, are dubbed in Dutch...
She has a wide variety of Children TV programming, in Dutch

The french germans, italians and spanish folks, often a lot less fluent in English, they often understand it, but don't speak it as well... why , dubbed movies, dubbed TV shows and a lot of native language kids TV...

you gotta be immersed with a language to pick it up
the earlier the better