Protists use chemical signals to communicate. The message depends on the chemical or mix of chemicals. They have receptors that take in the chemicals and are "decoded" in a certain organelle.
Annelid worms communicate with each other with touch and chemicals. different chemicals mean different messages.
Insects use sounds and scents to communicate. Different sounds and smells mean different things.
Amphibians also use different sounds to talk with one another.
Mammals communicate with sounds. Different sounds, pitches and lengths mean different things. Each type of mammal make different sounds. they can also use body language in some instances.