The sounds that the guinea pig makes correspond to its mood at a given time. A quiet whistle, and as the highest manifestation, a gentle “squeal” means satisfaction. The most common sound is a sharp whistle repeated at intervals of about one second. The pig gives this signal most often as a sign of greeting to a person she knows when it’s time to feed. 

The most piercing sound I have ever heard was a moan, which is an expression of pain. This is a very high-pitched and loud squeak, interrupted only for the duration of inhalation. It’s really hard to expect such a loud sound from a small animal. The last sound from the guinea pig repertoire that we are discussing here is a jabbering grunt that sounds almost like the echo of a drum roll. Usually it is used as a greeting to the encountered individuals, it also serves to lure the female to the male. Grunting grunts are also an integral part of sexual ritual. In this case, it is accompanied by the characteristic shoving movements of the animal’s body. I also heard a similar sound as a reaction of guinea pigs to unfamiliar situations or echoes. 

If you want to understand the guinea pig, try not only to listen, but also to look closely at it, often your animal expresses its desires not only with characteristic sounds, but also with certain body movements

• An insistent squeak means a clear need for food.
• A complaining squeak means fear or loneliness in babies. Animals kept alone express a desire to communicate with such a sound.
• Clucking and cooing sounds indicate that the guinea pig is happy and comfortable.
• Grunting sounds guinea pigs make at the moment of friendly greeting and sniffing each other.
• Roaring sounds are made by a weaker opponent in front of a strong opponent, which may be a person. If growling from fear turns into vigorous tapping of teeth, you should leave the animal alone, otherwise it will come to bites.
• The cooing sounds are made by the male, approaching the female during courtship.