Well Pharaoh`s daughter knew he was a Hebrew but Pharaoh would not have known or Moses would have been killed.
AS you say ,The Greeks called anyone who did not speak Greek, a barbarian " .
In Flemish the word "Babbelar"means a chatterbox, like a small child as we would say "babbling on"
.Also as we say" prattling", and in Flemish to praat is to talk, a prater is a talker.
Interesting links in different languages.
Viktoria.