It's tough to talk like a true Bostonian

Everyone in movies mangles a Boston accent. It flummoxed Robert Mitchum in "The Friends of Eddie Coyle." Robin Williams's stab at it in "Good Will Hunting" was like fingernails on a blackboard. The Kennedy accents in the movie and television takes about them over the years have been ghastly. Most recently, the stars of "Mystic River" sounded as if they came from five different countries, none of them in this hemisphere.

(The notable exception is Alex Rocco, who played Moe Greene in the first "Godfather" movie. But then Rocco grew up in blue-collar Cambridge.)

So why is the Boston accent so hard to nail?

"Because the Boston accent has gone off the map culturally," says Tim Monich, a top Hollywood speech and dialect coach. (Sean Penn called Monich about working on "Mystic River," but Monich was already in Romania for "Cold Mountain.")

"Before World War II, Boston was the cultural leader," he explains. "This changed during the war. It happened during the '40s. Between the '30s and the '50s, there was a difference in the ideal accent. In the '50s, Kim Novak was taught to speak in a way that was not like Hepburn."

Consider too, adds Monich, the number of movies that take place in Boston: "What, maybe one a year? But there are a ton with Southern accents, in plays and movies.

"There has to be some kind of root," he continues. "People have to have heard it. You go to the streets of Manchester, England, and ask a teenager to do a New York accent, and he'll give you something with a little bit of New York in it. Ask him to do a Boston accent? No way."

All true. But this still doesn't answer why an actor with uncommon accent skills cannot nail a Boston accent.

"I don't know," Monich concedes.

Indeed. He trained Rob Morrow in Robert Redford's "Quiz Show" to play the young Richard Goodwin with a Boston accent. It was a loser. "We only had two sessions," he says.

The mystery continues.

SAM ALLIS