My point is that not having access to a dictionary does not massively reduce one's ability to learn their own native language, not that dictionaries aren't useful.
I actually majored in Linguistics and will eventually wind up doing a Ph.D in it because I'm a horrific nerd. I love dictionaries and consult them literally every day for etymology information. That doesn't change the fact that, as I said, the absolute vast majority of someone's linguistic knowledge of their own native language is gained by observing the language used in context, not by explicit lookups in a dictionary. You don't teach a baby to speak by throwing a dictionary at it; you just talk to it and they figure it out.