If you were an actor or anchor or executive run aground on these sonic shoals, you might well have made your way to the Sam Chwat Speech Center on West 16th Street in Manhattan.

Founded in the 1980s, the center has helped thousands of clients prepare for roles, succeed in business or assimilate into the rushing stream of American argot by losing — or gaining — regional accents. Presiding was Chwat himself, a speech therapist who until his death last week was “Henry Higgins to the stars,” as The Globe and Mail of Canada put it in 1999.

Chwat helped Tony Danza, seeking broader roles, lose a New York accent, and Marcia Gay Harden, cast as Lee Krasner in “Pollock,” acquire one. (Harden won an Oscar for the role.) He taught Robert De Niro to sound Southern for “Cape Fear,” and Julia Roberts not to for nearly everything. He turned Willem Dafoe into a Transylvanian for “Shadow of the Vampire” and Olympia Dukakis into a Holocaust survivor for “Rose,” her one-woman Broadway show in 2000.

Chwat died Thursday in Manhasset, on Long Island. He was 57 and lived in Great Neck.

The cause was lymphoma, his family said.