The storybook character Dr. Doolittle has a comrade in northern Arizona. Both men believe that animals speak a tongue of their own, one that humans are just beginning to understand.

Language is supposed to be what makes people different from the rest of the animal kingdom, but some prairie dogs appear quite capable of holding their own conversations, according to Con N. Slobodchikoff, professor of biology at Northern Arizona State University in Flagstaff, Ariz."There's an incredible sophistication in the information contained in their calls," said Slobodchikoff, who has spent the past several years trying to understand the meaning of these sounds.

A language must have words with specific meanings and syntax so that word order affects the message. It must also have a set a rules - grammar - that dictates how words are strung together. The more researchers study animal communication, the more animal "words" they are able to pick out. A few like Slobodchikoff suspect the words have syntax, and that there may be grammar rules.

Vervet monkeys, it seems, have words for different predators. So do ground squirrels and birds. These alarm calls tell neighbors how to respond to danger and are important to the animals' survival.

A kind of prairie dog called Gunnison's may communicate a lot more about potential dangers.

"They can also incorporate information into their calls describing individual predators," said Slobodchikoff. Their barking is so fine-tuned that they seem to gossip about a person's height, weight and girth, and perhaps about a coyote's prairie dog-catching prowess.

The prairie dogs have eight types of calls. Slobodchikoff focused on one type, the alarm call.

During 200 hours of observing the community, the researchers saw 19 coyotes, 55 dogs, 120 hawks and 14 people with guns approach. They witnessed nine kills by coyotes and 13 by the hawks. Slobodchikoff recorded then analyzed and classified the barks according to 12 traits, including timing and frequency, of the sounds.

He and his colleagues first discovered that alarms for hawks were very different from calls warning of pedestrian intruders and that calls were different for dogs, coyotes and people.

He then compared the calls of seven groups of prairie dogs when a particular person, and then a particular dog, walked through the group at a consistent speed and in a particular direction.

"Not only did we find that there were different words for dog and human, but they were pronounced differently," he said in a recent lecture. "There are apparent dialects in these calls."

In the laboratory, Slobodchikoff has recorded calls after he showed individual prairie dogs a person or a dog, or a ferret or a great horned owl, two predators the prairie dogs had never seen before. He found the prairie dogs had different, but common words for all four types of predators, even ones they had not seen before.