RETREAT FOR TENNIS BUFFS; Florida

Those funny sounds you hear rising from the orange groves near Tarpon Springs are mostly animal but occasionally human. Peacocks, 50 or 60 by someone's count , roam the carefully tended grounds of a resort named Innisbrook, rending the sky with their haunting cries. Near the tennis court can be heard the equally peculiar sound of Australian English, known down under as Strine.

If you wonder what happened to the once famous Australian tennis game (there were no Australian winners at Wimbledon this year), it is well represented at Innisbrook, where Terry Addison and Garry Cooper operate the Australian Tennis Institute (ATI). That's a fancy name for a series of men's, women's, and family clinics given most of the year by the two golden-bearded Aussies, who look more like a pair of sea captains than the well-drilled players and teachers they are.

Florida, strong on golf and white-sand beaches, is fast becoming a tennis retreat, and ATI is one reason. Others are Amelia Island Plantation (19 gorgeous seacost courts and serious clinics run by All American Sports of New York City) and Sawgrass, two resorts near Jacksonville; Boca Raton Hotel and Club, whose 22 courts are overseen by the former Australian star Warren Woodcock; Palm Beach Polo & Country Club; and Harry Hopman's International Tennis, not far from Innisbrook at Largo, Fla., where the legendary "Hop," father of Australian tennis and more recently the trainer of American champions, runs a 42-court tennis incubator.

My game needed help (unsteady backhand, uncertain serve for starters) when I submitted it for ATI inspection a few months ago at Innisbrook. Having already graded yourself in a questionnaire, you arrive on Thursday to be analyzed on court by a video-tape machine and in a brief hitting spell with the Australians or their Ohio assistants, Karin Gaiser and Mary LoPresti. Friday and Saturday there are sessions from 8:30 to 11:30 a.m. and 2 to 5 p.m., followed by a final class on Sunday morning, after which you receive a diploma and a grading chart.

Though he spends much of his time strolling from court to court to check on the progress of the dozen or so students, the 36-year-old Addison frequently throws himself into the action to demonstrate a point. He is, after all, the main draw of ATI, a one-time member of the Australian Davis Cup team, who first set up his institute at Pinehurst, N.C., before retreating to Florida's west coast in 1980. It is the 30-year-old Mr. Cooper, though, who provides the yeast.

Impish, energetic, acrobatic, Garry Cooper starts the day off with a series of courtside warm-up exercises that include a kangaroo hop he borrowed from his favorite animal back home. Given the chance, Cooper is as likely to expound on the habits of Australia's animals as on the fine points of tennis. One day during a Gatorade break under the insistent Florida sun, he explained the birth process of the kangaroo. And during a warm-up, hopping around on one leg, he noted there are 17 million kangaroos and 14 million people in Australia.

Although he played collegiate tennis at Wake Forest in North Carolina, Cooper has long since quit the competitive circuit. Teaching is his game. He says so almost apologetically, but he needn't. The tedium of tennis instruction -- feeding thousands of balls a day to often reluctant pupils, shouting the same advice over and over -- can make even the best pro seek other employment.

I think he and Addison were a little surprised when a fellow student and I approached them the second morning and asked if they'd work us harder, run us faster. We had been fed hundreds of balls in drills on the basic strokes -- forehand, backhand, volley, overhead, serve, and return of serve -- but generally in a stationary position. Don Diehl of Easton, Pa., and I wanted more of a workout. Cooper's eyes lit up, and that afternoon the Kangaroo Kid took us both on at once, running us around the court like two mechanized toys and returning everything we hit, all the while shouting bits of instruction and encouragement.

There was competition that week not only from the screeching peacocks but from the pounding and drilling on a new tennis and racquetball center on the fringe of the 19-court outdoor layout. The center, with six racquetball courts, lounge, and tennis shops, looks across courts, golf fairways, and citrus groves toward the Gulf of Mexico a few miles away.

Innisbrook's 1,100 condominiums are spread through 10 lodges. They are comfortable and well tended, if not especially inspired in design. There are four golf courses, swimming pools, restaurants, and nightclubs spotted through the pretty, sprawling acreage with its stunted mossy cypress trees, pines, oaks, and abundant wildlife: ducks, birds, alligators, snakes.

We graduated Sunday morning beneath a grapefruit tree beside the courts. My final grading sheet shall remain a secret. Besides, who would understand? It's written in Australian.