Here's a breakdown:
* Newborn: Guinea pigs make soft, squeaky noises even in the nest. This is mostly for communicating with their mothers.
* Pups: As they grow, their squeaks get louder and more varied. They squeak for food, attention, and to play.
* Adults: Adult guinea pigs still squeak, but their sounds become more complex. They might squeak to warn each other of danger, express excitement, or even show affection.
So, to answer your question directly, guinea pigs start squeaking almost immediately after birth.