NYACK, N.Y. (AP) _ Comedian Myron Cohen, who for more than a quarter of a century entertained audiences with stories told in dialect, has died of heart failure at Nyack Hospital. He was 83.

Cohen, who died Monday, had worn a pacemaker for some time and suffered a heart attack in September, said his nurse, Vivian Stowbridge. She took him to the hospital from his home in nearby New City earlier that day.

''I'm so shocked, I can hardly talk,'' said fellow comedian Henny Youngman.

''We've been friends for something like 50 years, and we've been pals for years ... we've been to a lot of shows together and he was the best story- teller around in the last 40 years.''

Cohen, whose last public performance was in 1984, was a perennial favorite at nightclubs and resorts around the country.

He was a former salesman in the silk industry and began as a comedian with a routine at Leon and Eddie's nightclub in New York, said Jerry Sager, a family friend and Cohen's former publicist.

Later, he appeared at New York's Latin Quarter nightclub, and worked for many years in clubs in Las Vegas, Nev., Lake Tahoe, Calif., Atlantic City, N.J., the Catskills and other nightspots around the nation.

Although Cohen, a native of Poland, had no foreign accent in normal conversation, he developed a facility for reproducing the dialect of his Eastern European colleagues in the garment district.

He told his stories mostly in a Yiddish accent, but did Irish and Italian as well.

''Taste is the key,'' he once told an interviewer. Noting that many dialect comedians had fallen out of favor because they were perceived as ridiculing minority groups, he said: ''It was never the dialect that offended - it was the stories that were told. The Irishman was always drunk, the Jew was avaricious, and the Negro stupid. It became monotonous and tasteless.''

He told another interviewer some of his more popular jokes:

''An Italian gentleman goes into a bank to borrow money and they tell him the loan arranger's out to lunch. 'Well,' he says, 'if the loan arranger's out to lunch, I'll talk to Tonto.'''

He began again: ''Picture a skinny little guy, a shrimp, a nothing. He walks into a lumber camp looking for a job. To impress a skeptical foreman, the shrimp fells a towering oak in 90 seconds. 'Where'd you learn that?' says the lumberjack. The little guy says, 'In the Sahara Forest.' 'You mean the Sahara Desert.' 'Sure, now.'''

After his illness forced him to stop working, Cohen was cared for at home. He had lived in New City for more than 30 years.

Services were scheduled at 11:30 a.m. Wednesday at the Riverside Chapel in New York.

Cohen's wife, Miriam, whom he married in 1925, died in 1981.

Survivors include two brothers, Philip Cohen of Fort Lee, N.J., and Milton Cohen of New York; and two nephews, Burton Cohen of Rivervale N.J., and Dr. Mitchell Cohen of Cincinnati.