MONTREAL — A few years ago, the Quebec comedian Sugar Sammy put a giant ad on a Montreal subway billboard. “For Christmas,” it said, “I’d like a complaint from the Office de la Langue Française,” the Quebec watchdog responsible for preserving the French language.

His plea did not go unnoticed.

In Quebec, a French province surrounded by an English majority in the rest of Canada, sensitivities about language are profound, and large billboards must typically be only in French. Beyond prompting a complaint to the agency from an irate Montreal lawyer, the stunt spawned a loud debate about language, along with a death threat from a Québécois nationalist at his next show.

A fearless comic with a talent for provoking both laughter and outrage, Sammy, born Samir Khullar, is a 42-year-old son of Indian immigrants. He is also a child of Bill 101, the polarizing Quebec law behind the sign infraction, which requires immigrants to send their children to French schools. As a result, he glides effortlessly between English and French in his shows, and has made Quebec’s tortured identity politics his main preoccupation.

“Humor allows you to address taboos,” said Mr. Khullar, whose parents came to Montreal from northern India in the 1970s and who is far more soft-spoken in person than his swaggering, expletive-fueled stage persona would suggest. “In Quebec the ultimate taboo is identity,” he added.