'Gooo goo ga ga' (or goo googaa gaa), is a stereotypical baby 'talking'. When a baby says 'goo goo ga ga', it is usually considered humerous. However, I don't know if babies actually ever say this phrase.
The noise of an annoying baby, could be a babygirl, a babyboy, or your 4rth grade classmate trying to be funny but failing miserably... or maybe a Lady Gaga joke.
