Older? Yeah. Wiser? Well, Still a Wiseguy.

Sid Caesar, who turns 80 on Sunday, hasn’t lost the touch that side-split a nation during his reign as early television’s king of comedy.

Not one for the quick-hit zingers typical of that other TV pioneer Milton Berle, Caesar was always a sketch comedian who could lose his own persona in a variety of outrageous characters and “languages.”

During a recent interview at his sprawling hilltop estate, Caesar delivered hilarious monologues that sounded alternately like French, Italian, German and Japanese but actually were pure gibberish.

During his heyday, Caesar--along with co-stars Imogene Coca and Nanette Fabray, and second bananas Carl Reiner and Howard Morris--brought a new, more sophisticated kind of comedy to the American public.

Behind the scenes, however, there was a different Caesar--the madman portrayed in the play “Laughter on the 23rd Floor” by his onetime writer Neil Simon. Caesar acknowledges that some of his actions might have seemed over the top.

On a hot day in the writers room, he would strip down to his shorts. He recalled: “People would come in and say, ‘Where’s your pants?’ I’d say, ‘It’s a hot day; I don’t want to get them creased.’ ”

Then there’s the famous episode involving another of his writers, Mel Brooks.

Caesar was performing nine shows a day at the Chicago Theater. Before the last show, he returned exhausted to his suite at the Palmer House and was enjoying a hearty meal when Mel complained about the stifling heat. “I wanna go out,” he kept insisting until Sid angrily said, “You wanna go out?!”

“I opened up the window, and we’re on the 18th floor,” recounted Caesar, who in those days lifted weights and was remarkably strong. “I grabbed him by the seat of his pants and his neck and I held him outside the window. ‘You wanna go out farther?’ I asked. My brother Dave grabbed me and pulled us both back in.”

Caesar attributes at least part of his behavior to the pressure of maintaining high-quality material while turning out 40 shows a year. He was unable to sleep and began relying on alcohol and sleeping pills. Years of psychotherapy and the patience of his wife, Florence, helped him acquire a degree of well-being. Also helpful: conversations with his alter ego.

In 1979, Caesar was in Paris filming “The Fiendish Plot of Dr. Fu Manchu,” Peter Sellers’ final film and a box-office bomb. The job was supposed to last six weeks, and went on for six months. Caesar was going nuts. So he began a conversation between himself, Sid, and the young Sidney.

“I’d talk to myself every morning,” he said, “and you can’t lie to yourself, because you know what you feel.” When Sid complained about being stuck on the location, Sidney chastised him for complaining when he was being paid to stay in Paris. Sidney won out, and Sid began appreciating the art museums and making friends with locals.

Today’s television generation scarcely knows Sid Caesar. Unlike most TV classics, “Your Show of Shows” (1950-1954) and “Caesar’s Hour” (1954-1957) did not fit the sitcom pattern. And having been broadcast live, they were preserved as kinescopes, a crude form of video recording, not the 35-millimeter motion picture film of sitcoms. Hence they lacked appeal for syndicators.

But now, thanks to digital enhancement, young people can see what enthralled their parents and grandparents. Blagman Century Media of Santa Monica has released “The Original Sid Caesar Collection,” a three-tape set of videocassettes with selections from his two TV series picked by Caesar himself. “They look brand new,” he said proudly.

No wonder the shows were great; they boasted the most talented writers in show-biz history. They included Simon, Brooks, Reiner, Larry Gelbart (creator of the TV version of “MASH”), Michael Stuart (“Hello, Dolly,” “Bye, Bye Birdie”), Joseph Stein (“Fiddler on the Roof”) and a 20-year-old named Woody Allen.

Unfortunately, it was the shows’ smartness that helped bring their demise.

Demographics played the villain. Television’s early growth was centered in the big cities where the audience appreciated the quality of a sophisticated Broadway revue. As the Federal Communications Commission issued licenses across the country, television spread to the hinterlands. The networks’ search for an ever-widening audience resulted in the dumbing down of programming.

When his second series was canceled, Caesar was in the midst of his own “20-year blackout,” as he recounts in his 1982 autobiography, “Where Have I Been?” Not until the 1970s did he reach a degree of stability.

He took over the leads in two Neil Simon plays: “Last of the Red Hot Lovers” and “The Prisoner of Second Avenue” (he had starred in another Simon play, “Little Me,” in 1962). He appeared in such films as “It’s a Mad Mad Mad Mad World” (1963), “A Guide for the Married Man” (1967), Mel Brooks’ “Silent Movie” (1976) and “History of the World, Part I” (1981), and Simon’s “The Cheap Detective” (1978).

Caesar and his wife of 59 years live high above Beverly Hills in a spacious house that resembles an overstocked art gallery; several of the paintings are by modern classic artists. Though he appears on a few TV shows, often to receive an award, he quit performing eight years ago.

“There’s a time to know when to hold ‘em, and a time to know when to fold ‘em,” he said, quoting the Kenny Rogers song. “You’re never going [to perform] as you did when you were 27. After you get past 60, you don’t want to be seen like that.”

Nonetheless, Caesar wears his 80 years well, considering the self-destructive period, triple-bypass heart surgery and other health problems. His round face has thinned, and he uses a cane to get around. But he walks up and down the hills near his house every morning and spends much of the day pursuing his favorite hobbies: reading history and physics books. Not bad for a boy whose formal education ended with a diploma from Yonkers High.

Caesar’s Polish immigrant father ran a restaurant in a multiethnic section of Yonkers.

“That’s where I learned to do the languages,” Sid remarked. “When I picked up the dishes, I listened to the Italians, the Germans, the French. Each language has its own rhythms.”

Young Sid didn’t set out to be a comedian; he started as a musician, playing sax, clarinet and sometimes flute in the bands of Charlie Spivak, Shep Fields, Claude Thornhill and Benny Goodman.

While appearing in the Catskills with a five-piece combo, he was asked to do a slapstick skit. The audience roared, and he was hooked.

Contemplating his Sept. 8 birthday, he mused:

“Eighty years old, that’s a good number. My legs are not as good as they used to be, my back gives me a little trouble--the usual things that go along with age. These are the cards you’re dealt; play them. You can’t keep taking pills for the pain. You live with the pain.”

He added slyly: “I wanna stick around to see how it all comes out.”