Three reasons why tonight’s Celtics-Nets game is an extremely big deal:

1. This is the first game Marv Albert — who was born in Brooklyn, as Marvin Aufrichtig, in 1941 — has ever called in his home borough.

2. That’s big on your basic, local-boy-makes-good level.

3. That’s big beyond that level, because hometowns aren’t simple things. Brooklyn, for example, is where young Marv taught himself play-by-play. But Brooklyn is also the accent he spent years trying to lose. It’s where his first surname, Aufrichtig, was taken away. Marv, in other words, is something more complex than Marty Markowitz. If we study the things Marv took from Brooklyn, and the things he had to leave behind, then we can see the formation of the man who will inevitably unleash a “Yes!” tonight.

OK? Let’s join young Marv Aufrichtig, in Brooklyn, around 1957

The Aufrichtig brothers — Marv, Al, Steve — had a ritual. After dinner, they’d walk from the dining room into the living room and close the door. They’d turn on whatever baseball game was on TV. And then they’d turn the sound way down.

They placed a table in front of the television. Marv, who was the oldest by six years, took a seat on the right. He did play-by-play. Al sat in the middle. He was in charge of a sound-effects record that replicated crowd noise. Steve sat on the left. He had two price-marking pencils from their father’s grocery store, and when he hit the pencils together, the sound mimicked the crack of a bat.

The Aufrichtigs would begin broadcasting. In front of the boys was a Wollensak reel-to-reel tape recorder, which captured every word. They did this almost every night. After a couple of innings, they switched places.

Their two-story house was in a neighborhood called Manhattan Beach. It’s an odd little suburban corner of south Brooklyn, where the streets have British names like Oxford and Amherst. The Aufrichtigs lived at 178 Kensington. If you walk half a block north on Kensington, you run into a channel thronged with Russian fishermen. Walk half a block south and you find a big park with basketball courts, and beyond that, the Atlantic Ocean.

Max Aufrichtig, Marv’s dad, was a Hungarian American who owned a grocery store. He liked the Dodgers. His wife, Alida, preferred music. It was Alida who answered the phone one day and found Stan Musial on the line — Marv, posing as a journalist, had called Musial’s hotel and left an urgent message.

The three brothers often think about why they spontaneously decided to become sports announcers. First they offer the Failed Athlete Theory. Meaning, none of them were Connie Hawkins. Al Albert — who later became the play-by-play man for the Nuggets and Pacers — says Marv “left his lethal 7-foot jump shot on the courts in Manhattan Beach.”

The Aufrichtigs also offer the Brooklyn Theory. Which is that they saw their home borough as a sports arena in need of announcers. Marv would peek out the small window of his second-floor bedroom onto Kensington Street. If a roller hockey game happened to be in progress, he would begin to call it.

When the weather was lousy, the Aufrichtigs would stage a “rain delay” and replicate network time-fillers. (The raindrops hitting the overhang of their basement door added authenticity.) They had a Ping-Pong table in the basement. “Two of us would play,” Marv remembers, “and the other would be a play-by-play announcer. It’s kind of sick.”

An imaginary announcers’ booth might have been a standard brotherly project, like a pillow fort, and forgotten the next day. Except the Aufrichtigs took the next step and started listening to their tapes. They heard Brooklyn accents. R‘s were added and deleted. “Russia” became “Russier,” and “park” became “pawk.”

This was no good. The New York airwaves could accommodate southern twangs (like Mel Allen and Red Barber’s), and the local sportscasts could hire ex-Giants who were still learning how to talk. But an outer-borough accent was somehow too local, too provincial. This is why the Bronx’s Vin Scully and Brooklyn’s Al Michaels — yup, him — now speak with an untraceable smoothness. “I think I’ve lost most of it,” Marv says of his accent. Whether that’s true or not, you see how hard he has worked at it.

The listening sessions on Kensington Street, then, were also diction lessons. “We would critique ourselves,” says Steve Albert, who’s now the play-by-play man of the Phoenix Suns. Steve pauses, as if he’s remembered something. “I’m like 7 years old at this point!”

As a teenager, Marv got a job at 215 Montague Street working for the Brooklyn Dodgers, a gig he earned after appearing on a radio show, All-League Clubhouse, as a child panelist. As a “very significant office boy,” Marv managed the giant public scoreboard the Dodgers kept atop the building. The cool thing was, Ebbets Field became his new arena for fake broadcasting.

On game days, Marv hauled the giant Wollensak tape recorder onto the bus in Manhattan Beach. The recorder was about the size of an accordion — only klezmer bands suffered more for their art. Marv hoisted it onto the subway. Then up the stairs to the employee side of Ebbets Field press box, between home plate and first base.

From there, only a thin wall separated Marv from Vin Scully, the Dodgers play-by-play man who’d replaced Red Barber in 1954. “He had this different, mellifluous voice — it was almost poetic,” Marv says. “What I admired about him was the preparation of anecdotes.”

At every game, Scully would deliver prepared anecdotes to Brooklyn, and Marv, who was 16, would deliver prepared anecdotes into a tape recorder.

“I’d usually have a friend or one of my brothers as a color commentator,” Marv says. One of the color commentators was the forefather of Gus Johnson. He screamed. Finally, Dodgers owner Walter O’Malley sent word that the fake broadcast team needed to move. Marv and his team relocated down the right-field line. “We didn’t have quite the same vantage point,” he says. He kept broadcasting.

Marv estimates he “called” at least half of the 77 home games the Dodgers played in 1957, their final year in Brooklyn. After the games, Marv would wait for Scully to clear out. Then he would enter the broadcast booth. It’s tempting to make something mystical out of this — Marv and Vin, sharing the same turf. But Marv was not mystical. Marv was practical. He gathered up the commercial scripts Scully had read and then dropped on the floor. On Marv’s next “broadcast,” he’d read them, too.

Lincoln High School. Coney Island. He’s 17 now, with big ears and black hair styled as a retaining wall atop his forehead. During basketball games, he lugs the recorder up the bleachers, into the second deck, and starts his imaginary broadcast. Did his classmates think this was odd? “Not really,” Marv says. “The players always wanted me to play it back after the game so they could hear what I said.”

This October, I got off the F train at Neptune Avenue, walked through the courtyards of two housing projects, and through the metal detector at Lincoln High. On the ground floor, there’s a list of names in gold stencil marked “ATHLETIC HONOR ROLL.” Marv’s name isn’t on this list. I found it two floors up, on a list marked “PUBLICATIONS HONOR ROLL.” There it is, “Marvin Aufrichtig,” the old surname still intact.

Lately, Lincoln High has been famous for producing Stephon Marbury and Sebastian Telfair. But in the ’50s, it was a Jewish and Italian stronghold that turned out Neil Sedaka and Neil Diamond. Sports were huge. Ken Auletta, Marv’s classmate and the future New Yorker writer, pitched for the Railsplitters baseball team. “I once had two strikes on Joe Pepitone,” Auletta says. “I decided I was going to throw him a change. The ball is still going.”

Marv was a sportswriter for the student paper, the Lincoln Log. A librarian and I found his old clips in a state of mild disintegration. As a junior, Marv seems to have busied himself with reportage — i.e., “The October 12 game with Brooklyn Tech was lost to the flu epidemic.” He dubbed the track team the “spike-shoed delegation.” As a high school journalist, he probably thought that was a scream.

But by his senior year, there were signs of the Aufrichtig Dry Humor. The wryness that, decades later, would be put in the Late Night sketch in which David Letterman gets asked what happens when a guest doesn’t show, and we find Marv in a box marked, “In Case of No-Show, Break Glass.” Comedic influences are harder to trace, though around this time Marv was attending lots of tapings of Johnny Carson’s Who Do You Trust?

Marv began his November 10, 1958, Lincoln Log column like this:

Every once in a while, generally when sports activity is at a low ebb and journalists have to dig deep for their stories, the so-called dot-dash column is created. As a matter of fact, one cannot be considered an official member of the sportswriting fraternity until he has successfully sneaked one of these jobs into print. So, here goes ”

Dot-dash — the art of squeezing non-nutritious factoids between ellipses. Marv took the concept and ran with it: “The uncrowned hero of the Lincoln Football Team is student trainer Bob Ornstein The student who wonders why he has to study decimal fractions gets his answer when figuring baseball percentages If halfback Munro Fresier’s knee heals sufficiently, he may take a whack at the high hurdles. He’s a natural!”

As a teenager, Marv had executed a preemptive parody of Larry King’s USA Today column.

It was the Dodgers leaving Brooklyn, ironically, that made Marv turn his full attention to basketball. By 1957, he was a ball boy and the president of the Knicks fan club. That November, the Knicks offered to let him tag along on a road trip to Philadelphia. Marv met the players at Penn Station and everyone took the train.

His account of the trip appeared under the headline “On the Road With the Knicks” in the next month’s issue of the Lincoln Log. “The tall group of individuals were the New York Knickerbockers; the shorter party, yours truly,” Marv wrote.

The ’57-’58 Knicks were awful — fourth in the four-team Eastern Division and jobbers to the Celtics, who’d drafted Bill Russell the year before. On the road trip, the Knicks were whipped by the Philadelphia Warriors — and out of courtesy, Marv declined to put the score in the Lincoln Log.

What Marv did on the train that afternoon was watch. He watched Ray Felix, a 6-foot-11 center, do card tricks “with the old form of yesteryear.” He noticed that Willie Naulls, a power forward from UCLA, fussed over his clothes. Kenny Sears, who in college became the first basketball player on the cover of Sports Illustrated, told horrible jokes.

Marv befriended Marty Glickman, the Knicks announcer who’d grown up in Brooklyn, too. But the key to Marv’s Knicks period was his observations. Coaches like Auerbach let him eavesdrop on pregame talks. “They were so basic,” Marv says. “They were so fundamental. Now, you’ve got four, five coaches on the bench and there’s more strategy involved. But then it was taking advantage of matchups, and if you had the better players, you usually would win.”

You see what’s happening here. For Marv, athletes are slowly being stripped of their mysticism. Marv didn’t become a suck-up, the announcer who gleans a few “scoops” for a lifetime as the athlete’s unofficial wingman. It’s more like he made players into his co-conspirators.

“Kenny Sears’s stale jokes put the other players to sleep,” Marv wrote in the Lincoln Log in 1957. Now, fast-forward three decades. Remember when Michael Jordan hit six first-half 3-pointers in the ’92 Finals and gave that I-can’t-believe-it-either shrug? It’s often forgotten that the guy he was shrugging at — his co-conspirator, you might say — was the NBC announcer whom he liked so much that he’d feel hurt if he didn’t get asked for an interview. The guy MJ was shrugging at was Marv.

In the summer of ’59, Max and Alida Aufrichtig gathered their sons around the dining room table. After listening to a few hundred hours of pretend sports broadcasts, the couple had made a decision. “Fellas,” Max told his sons, “just in case you guys ever get anywhere, I’m going to make it easier on you. I’m going to shorten our name.” Their new name was Albert.

The boys were stunned. “Do we get a say in this?” Steve, the youngest brother, asked.

Max ignored that. “Your mom and I went to the phone book and we looked under the A‘s,” he continued. “We wanted to keep an A name.” That was the end of the conversation.

Years later, Marv says, I thought, How’d he come up with that? Was it because of the initials on the towels? Then, more seriously: “I think about this. I wonder today if I would have done that.” Just like the accent, it was a part of Marv’s Brooklynness that got scrubbed.

The next time the Aufrichtigs signed onto their imaginary broadcast behind the living room door, Marv said, “This is Marv Albert ”

“When it was consummated,” Steve Albert says, “my mother had to write a note that I had to give to my fifth-grade teacher, Mrs. Shaughnessy, at P.S. 195. I handed her the note. She was a very imposing woman — a tall woman. She looks down at me, closes my note, and says, ‘Class, Steve has a new name.’ And they applauded!”

In January 1963, Marv was a radio writer when Marty Glickman, the Knicks play-by-play man, got stuck on assignment in France. Glickman suggested that the kid who’d been hanging around could broadcast Knicks-Celtics, in Boston, the following afternoon. “I always felt Marty might have gotten back [to the U.S.] and was looking for an opportunity to put me on,” Marv says. “He denied it. But I think he did.”

Marv got on the first train to Boston. He brought Al Albert to do the stats, because who else was going to do it? Steve demanded to tag along, too, but his parents said he couldn’t just go to Boston. Steve was 9.

“I brought my recorder with me,” Marv remembers. Al remembers Marv buying all the newspapers when they got to Boston at 3 a.m., and then spreading them over the bed in the hotel. “I recall sleeping under a Dick Young article,” Al says.

Marv studied the papers past midnight. Preparing anecdotes. Then he turned on the tape recorder and spent the rest of the night listening to his own voice. Diction, pronunciation, accent.

When Marv and Al got to Boston Garden the next day, a guard wouldn’t let them in. He looked at the pair — a 21-year-old and a 14-year-old — and thought, C’mon, they’re the announcers? Finally, Knicks guard Richie Guerin happened by and said, “Oh, they’re OK!” A few minutes later, Marv got behind the microphone and said, “This is Marv Albert ”

Steve Albert was listening in the living room at 178 Kensington, the site of the fake broadcast booth. “It was like it all came to fruition,” Steve says. “It felt like we were one person, almost. I never said that to Marv. It felt like he was all of us.” Soon after, the Knicks made Marv a regular fill-in, and the boy formerly known as Marvin Aufrichtig, of Brooklyn, had made it. He had a gig. In Manhattan.