"Uh-oh" is the universal toddler phrase to mark any event. If there were such a thing as a toddlerspeak - English phrasebook, Uh-oh would take up fully half of it.

It can mean, among other things:

• I dropped something.
• Someone else dropped something.
• I've just fallen over
• I just saw something happen
• I just turned you computer off at the wall socket. You had saved, hadn't you?
• A windmill just made a noise
• A vessel has been detected

It is also unutterably cute.