bigmamma - your story has made me remember some things my nephew and niece used to say, that left the adults biting their lips to stop laughing. (Nothing worse than a little one working out that adults laugh at certain things...!) My niece couldn't say 'that one' and always said 'rat bum' and got quite cross when we kept saying 'this one?' pointing to the wrong thing so she'd say it again and again.
The best, (or worst, whichever way you look at it!) was my nephew, who couldn't say 'swimming trunks' and instead said, as clear as day and no exaggeration, 'wimmin c x x x s' And that really is the truth! You can imagine how keen my brother was that we all said 'cozzie' in front of him instead, and woe betide anyone who laughed, or even smiled too much...