LEO ROSTEN, WROTE `JOYS OF YIDDISH'.

Byline: The New York Times

Leo Rosten, the writer, scholar and language maven who introduced millions of Americans to the deep lexical pleasures of chutzpah and shlemiel and kibitz and nosh, died Wednesday at his home in Manhattan. He was 88.

Rosten, who wrote dozens of works of fiction and nonfiction in a career that spanned more than six decades, was best known for his books celebrating Jewish language, humor and culture, including ``The Education of HYMAN KAPLAN'' (1937) and ``The Joys of Yiddish'' (1968).

``The Joys of Yiddish'' was a fat lexicon of expressions - from alter kocker to zaftig - that had elbowed their way into ordinary English idioms, endearments, epithets and jokes.

As Rosten described the book's purpose in his introduction: ``It illustrates how beautifully a language reflects the variety and vitality of life itself; and how the special culture of the Jews, their distinctive style of thought, their subtleties of feeling, are reflected in Yiddish; and how this in turn has enhanced and enriched the English we use today.''

Over the years, ``The Joys of Yiddish'' has become the de facto standard reference work on the language, serving as a bridge between Rosten's forebears and the more assimilated readers of our own age. Although the book quickly became a best seller, critic Irving Howe kibitzed Rosten in The New York Times Book Review for uprooting Yiddishisms from their larger cultural context and for shlepping out Borscht Belt humor that was already old in his grandparents' day.

``Let Howe write 10 jokes and let me write 10 jokes, and you'll see the difference,'' Rosten countered.

But in the end, it was Rosten's mother - who then? - who had the last word. When ``The Joys of Yiddish'' was published, she telephoned her son the writer. ``You have saved Yiddish,'' she told him. ``A leben auf dein keppeleh'' - a benediction that translates literally as ``a life on your little head.''

What united Rosten's output was his finely tuned ear for language in all its richness. In his books, he guided readers through the nuanced worlds of meaning that lie hidden beneath a joke, an idiom or a vocal inflection. And what he revealed was nearly always good for a laugh.

``Humor is an indication of a wholeness of character structure,'' Rosten said in a 1981 interview. ``Indeed, I would say that one of the requirements for sanity is a sense of humor - and its absence is crippling.''

Rosten's delight in the comic possibilities of language was nowhere more evident than on the lips of his most famous creation, Hyman Kaplan, whom critics have compared to the comic characters of Dickens and Shakespeare. Inspired by a former night-school student from Rosten's own teaching days, Kaplan, a Mr. Malaprop by way of Ellis Island, embodied both the perils and the pride of the immigrant experience. Hyman Kaplan made his debut in 1935 in a series of New Yorker stories; the stories were later published in book form under the pseudonym Leonard Q. Ross.