I work for a nice family. I hope they aren't regular readers of my blog because I am going to quote one of them (from memory, so not very well, but I feel like it's an important thing to think about).
"You try to figure out tricks to keep social interactions going, when you have a child who is often unresponsive. Someone asks them a question and the person is waiting and waiting, and so then finally you say okay, and you say something to keep the interaction going. But over time, the time before you answer keeps getting and shorter, and your child is getting phased out of the interaction."