Well, DS has just started Year One and tonight, from nowhere, without being prompted, I have just had an hour long conversation with him about his class, his friends, who he sits with at what lesson, what he likes best, who is naughty who is good, what he overheard his teacher saying about him, what he thinks of the playground, what happens when someone falls over and everyone looks after the child that's hurt while one runs for the teacher! It was like a switch went on!
After many years of getting the same response I now ask friends dcs for 'news'.
What I do when I pick dd3 up is to ask what was the best thing that happened today and what was the worse thing that happened today.
That normally gets some sort of response and MAY even prompt her to tell me TWO things
I had the same thing for ages when DS1 started nursery.
What did you do today? Played with cars and toys.
That's all he ever said.
As part of bedtime routine I will tell him what I did that day, then he will usually tell me something he did. It's a work in progress.
or just don't ask, it's their world, they haven't really had their own space before that you didn't know all about - let them revel in it.
When I pick ds1 (reception) up I say "have you had a good day?", and that is it.
He has now started to talk about it at tea-time or in the bath, but I just respond to his questions, rather than pushing him.