>human children learn to understand and use language — an incredibly complex and nuanced domain, to say the least — with shockingly little data and often zero-to-none intentional instruction

This isn't accurate comparison imo, because we're mapping language to a world model which was built through a ton of trial and error.

Children aren't understanding language at six months old, there seems to be a minimum amount of experience with physics and the world before language can click for them.