Even stranger example of this: when I was about six months old, my mother made a cassette tape of my "baby talk." Years later she listened to the tape: and I wasn't babbling, I was speaking understandable words. Under the stress of caring for a small child, you don't actually notice details that are obvious to a non-parent observer.

Interesting! My experience is mostly in the opposite direction, i.e. the baby saying things that only the parents understand, for others it's just meaningless babble ("He said he was hungry!" "No he didn't, he said "muh").