Human languages are massively redundant specifically to enable this kind of "fill the gaps" learning process.

Observe an unknown word used a few times in different contexts, and you'll get a very good bead on what it means.

It's the "natural" way of learning a language. No one gets every word explained to them in detail - most words you know in your own first language are the ones you picked up on the go.

I think this "structural redundancy" might be a big part of what enables LLMs to learn human languages "from nothing".