On one hand I am always amazed at what kids can learn and latch onto in the weirdest ways. So I have no doubt that a lot can be learned through context. Watching movies can absolutely demonstrate a seemingly endless scenarios in a way that can be understood.

However, as someone raising a child, let me tell you how often I have to stop and explain that certain things are not real just because there's a video of it. Or how many words are being used incorrectly because they were heard in one context that was misunderstood.

I think a child who only had media to teach them, with no one to correct things, would have an endless amount of misunderstandings - nevermind the amount of things they'd believe that are entirely fictional. Basically, no, this kid would be screwed.