Lyndon Johnson and Richard Nixon had "dynamic" speaking styles. Dwight Eisenhower's was "sermonic." Harry Truman's was "pugnacious." John F. Kennedy's was "cool," and Gerald Ford's and Jimmy Carter's were "highly tentative."

These are the judgments of Dr. Roderick Hart, a University of Texas professor who turned speech patterns of the seven presidents over to a computer. The ensuing analysis, he said, surprised him.

"I would not have predicted anything as leaden as a computer would be subtle enough to pick up the feistiness of Harry Truman, the rather ethereal nature of Dwight Eisenhower or the inability of Jimmy Carter to sound realistic," Hart said.

In a four-year project, he analyzed 266 major speeches -- 38 for each of the presidents -- which were delivered between 1945 and 1976. The findings were published in the spring issue of the magazine Discovery.

"Harry Truman's 'buck-stops-here' attitude carried over into his public remarks," Hart said. "Truman scored much higher on the rigidity scale than any of his successors. His famed, pugnacious image seems to have resulted from his consistent use of terms like 'always' and 'never.' He rarely used 'weasel words' or other expressions that are hard to pinpoint."

According to Hart's analysis, Johnson and Nixon "talked like presidents, or at least in a manner perceived by Americans as presidential. Their language was dynamic, concrete and uncomplicated. Neither of them left any doubt that there was a power-wielding president in the White House.

"When inspecting the language of Gerald Ford and Jimmy Carter, however, one looks in vain for the same sort of presidential thrust," said Hart. "Both were passive, highly tentative . . . Missing in their remarks was the assured voice of Harry Truman or the pragmatism of a Richard Nixon. Missing too was was Lyndon Johnson's verbal energy." Hart said Eisenhower's "sermonic speaking style, resulting from his failure to use concrete terms, made Eisenhower ripe for parody."

And for all that has been written about the "Kennedy style," Hart said, the computer could find relatively little to distinguish it from others.

However, he said, "Kennedy rarely used the glib optimism common to politicians," and "he forsook the language of intense patriotism as well. In other words, Kennedy's style was a 'cool' one. He refused to become the nation's cheerleader."