Her peers seem to have grown out of this but she hasn't. Lots of examples but one just now, which has prompted this thread.
DD1, her sister(DD2) and a friend (all same age) are having dinner and I have just been serving it up and said "tell me when" and my DD2 and friend both said "when" and I stopped. DD1 then went into a long complicated explanation of why I didn't really want them to say "when", and how they should have said 'stop' or 'enough'. The other girls just looked at her in amazement, not so much her sister as she is obv used to it. They tried to explain that is was a joke but anything like that is lost on her.
It worries me that she is still so so literal, like a much younger child, when her peers have outgrown it.
That's prob a silly example, there are loads that I can't think of, she doesn't get any jokes really, just dissects them and wonders why they are supposed to be funny.