S.I. Hayakawa, 85, a noted semanticist whose willingness to confront striking student radicals at San Francisco State University in the late 1960s led to a career in politics and a seat in the U.S. Senate, died of a stroke Feb. 27 at Marin General Hospital in Greenbrae, Calif. He had been hospitalized for bronchitis.

A witty, independent and iconoclastic figure whose interests ran the gamut from jazz and African and Asian art to fencing and cooking, Dr. Hayakawa was the author of a classic work on the way people react to words and symbols. As a public servant, he was a hero to some and a villain to others, and he readily acknowledged that he hurt himself by his tendency to speak without thinking.

But it was action, not words, that first gained him prominence outside of academia. He had been interim president of San Francisco State for less than a week when he climbed onto a sound truck on the campus on Dec. 2, 1968, and ripped the wires from the loudspeaker during a student protest. The event was captured on live television, and the slender, soft-spoken scholar with a fondness for multihued tam-o'-shanters became one of the most popular figures in California. He was dubbed "Samurai Sam."

During the next several months, he broke student and faculty strikes and restored normal classes. An African studies program was added to the curriculum, a key demand of the protesters. But demands that African studies be entirely independent were refused, and the department was put under the same administrative network as other academic programs.

In 1973, Dr. Hayakawa resigned as president of San Francisco State -- he had been given the job on a permanent basis by Ronald Reagan, who was governor of California at the time -- and three years later he ran for U.S. Senate. A former Democrat, he joined the Republican Party and described himself as a "Republican unpredictable."

He was an instant success on the hustings. Although he later supported the treaties giving Panama ultimate control of the Panama Canal, he delighted conservatives during the campaign when he said that the United States should keep it, because "we stole it fair and square." On another occasion, when asked for his views on a referendum on dog racing, he replied that he didn't "give a good goddamn about greyhounds one way or another." In the election, he handily beat Democratic incumbent John V. Tunney.

In the Senate, his outspokeness and seeming indifference to appearances became a liability. He had long had a habit of dozing off in meetings that bored him, but when he did it during orientation sessions for new senators and later at such occasions as White House legislative meetings he drew wide criticism. He was known as "Sleeping Sam."

There were other troubles. Dr. Hayakawa had not even been sworn in when he was ridiculed for objecting to his assignment to the Senate Budget Committee on the ground that "I don't understand money at all {and} have the greatest difficulty even balancing my own checkbook."

He alienated many constituents when he said that rising oil prices were not a concern, because "the poor don't need gas, because they're not working." He angered many others when he defended the internment of 120,000 Japanese Americans during World War II as "perhaps the best thing that could have happened," because it helped integrate them with the rest of society later. He was a Canadian citizen teaching in Chicago during the war, and was not involved with the internment program.

In later years, Dr. Hayakawa sponsored a constitutional amendment to make English the official language of the United States, claiming that a command of English was "the fastest way out of the ghetto." He opposed bilingual education in public schools and bilingual ballots as "foolish and unnecessary."

Finding himself with little support by the end of his first term, Dr. Hayakawa retired.

"He was invaluable during some very difficult times -- a courageous man of integrity and principle," former President Reagan said in a statement.

Gov. Pete Wilson described Dr. Hayakawa as "a great California iconoclast," and said "certain images from S.I. Hayakawa's remarkable life will be burned into our memories forever."

Samuel Ichiye Hayakawa was born July 18, 1906, in Vancouver, British Columbia, of Japanese parents. His father, Ichiro Hayakawa, had served in the U.S. Navy as a steward and then returned to Japan to marry Tora Isono. They settled in Canada, where the elder Hayakawa established an import-export business.

"Sam" Hayakawa, the eldest of four children, graduated from the University of Manitoba and received a master's degree in English from McGill University. He received a doctorate in semantics from the University of Wisconsin. He taught there until 1939, when he moved to Chicago and taught at what is now the Illinois Institute of Technology. From 1950 to 1955, he was on the faculty of the University of Chicago. He then joined the English faculty of San Francisco State, which is now part of the California state university system. He became a U.S. citizen in 1954.

Dr. Hayakawa made his scholarly reputation with "Language in Action," which appeared in 1941. It was reissued in 1947 as "Language and Thought in Action," a basic text in the field of semantics, which Dr. Hayakawa defined as the "comparative study of the kinds of responses people make to the symbols and signs around them."

The book was prompted by the rise of Hitler and the way he used words and symbols to consolidate his political power. It makes the argument that words can be used both to disguise and distort reality and to illuminate it, and that words therefore are different from reality.

Dr. Hayakawa's late brother-in-law, the late architect William Wesley Peters, was married to Joseph Stalin's daughter, Svetlana, who gave birth to the former Soviet leader's granddaughter in the Hayakawa residence in Mill Valley, Calif.

Dr. Hayakawa's survivors include his wife, the former Margedant Peters, whom he met while he was teaching at Wisconsin, of Mill Valley; two sons; and a daughter.