Was this the first time they have ever spoken in public? I think so. I don't remember ever even HEARING them speak before in a normal circumstance like saying hello as they came off AF1 or something. If my first time speaking in public was at MSG for the re-election of my father I'd be nervous too! The speech could have been rehearsed more but that's about it. Very cute.
I have named my new computer & shopping cart in their honor.