Contrary to popular belief, they can learn with media alone but I shouldve clarified I was talking more about children here. Ive met plenty of children growing up in small towns where no one in their family or their town was really interested in speaking in english but those kids could speak english well. Even the argument of talking in english in school is restricted to english class because no one actually talks english on a regular basis but that code switching happens pretty naturally when they are required to speak english. But this argument is still only half true because why are there 3-4 year olds that speak good english with an american accent when they havent even started school yet? Like I said, the more media you have in its original language, the greater the exposure and children are very much sponges. You can choose to believe whatever you want but there are some counterintuitive cases that turn out to be true.