"...Poisonous little bird?"
"No, 'You sound disappointed, little bird.' Do you know what 'disappointed' means?"
So I explained it.
I did pretty much the same thing with my parents' friend Terry and the word 'unsanitary' as a kid. I hadn't encountered Terry as a name before... Fortunately, I was sufficiently inarticulate due to youth so that I was unintelligable to anyone but my parents.