Different sounds affect the behavior of different animals in different ways. When my guinea pigs hear me open a plastic bag, they squeak with excitement, because I store their lettuce in a plastic bag, and they want me to give them some lettuce. Usually I'm opening some different plastic bag that doesn't have their lettuce, but they're quick to tell me, with their squeaking, that they're hoping for lettuce.

Wikipedia has links to different sounds made by guinea pigs in different situations:

Here's an article in Wikipedia about sounds in Animal Communication:

You can start to notice sounds around you and look at the behavior of the animal or animals that are making the sounds or listening to the sounds. If you have a pet, that's a good animal to observe. You an check out birds and dogs in your neighborhood, too.