Guineas do chatter, squeal and grunt - quite a difference from quieter rabbits and rodents. Content guinea pigs, also called cavies, will make low-pitched versions of those sounds, as well as cooing noises. Generally, you'll hear these when you're cuddling or petting your guinea. Squeals usually greet food or treats as well. At least you will know that your guinea pig is appreciative of the meal.
Cavies love attention and they like to be with other guinea pigs.
Generally, a male-female pair is happiest, but that requires at least one partner to be altered so there's no risk of pregnancy. Neutering the male is often the easier of the procedures and, unlike with rabbits, there is little chance of an unspayed female cavy running a high risk of uterine cancer. A pair of females is often easy to keep together as well, but usually males are tougher to bond. If there is no female cavy in the house, you'll have better luck keeping two males together. However, they may still fight.