I'm coming to you from my lunch break at (wait for it) jury duty. Yes, you're right--this has been a really weird few weeks.
Anyway, today's topic is receptive language and how it can be years ahead of verbal or even sign language. It can be really easy to assume that what kids can indicate is also the limit of what they can understand. But for the majority of kids, the amount they receive and understand is months or years ahead of what they can say back.
I know that my older son got far less agitated, even as a 5-month-old, when I'd tell him where we were going and what we were doing before and as we went. And when he started to speak, his grasp of the vocabulary and concepts surrounding our normal schedule was advanced, as if he's always known it and was just waiting to be able to say it (which I think was exactly the case).
I've watched friends' kids pay attention carefully to situations, and then respond to questions about them by turning their eyes to the answer, at extremely young ages.
So I'm convinced that kids are taking in a ton, waaaaay before they're even close to being able to sign or say anything about it.
Can we share anecdotes or thoughts about receptive language? I'll start: When my older one was about 8 months old, I took him to my hometown and we went to a local pizzeria called Inky's and ate dinner with my brother and a friend. About 18 months later, back in my hometown, someone mentioned Inky's and my son (who was talking by then) blurted out "Hot pizza!" We were gobsmacked, as none of us had mentioned Inky's in the interim.
What have you got?