“There is something going on with him that we don’t know about,” Mr. Trump said of the president, drawing applause from the crowd in Washington.
The dark power of words has become the defining feature of Mr. Trump’s bid for the White House to a degree rarely seen in modern politics, as he forgoes the usual campaign trappings — policy, endorsements, commercials, donations — and instead relies on potent language to connect with, and often stoke, the fears and grievances of Americans.

The New York Times analyzed every public utterance by Mr. Trump over the past week from rallies, speeches, interviews and news conferences to explore the leading candidate’s hold on the Republican electorate for the past five months. The transcriptions yielded 95,000 words and several powerful patterns, demonstrating how Mr. Trump has built one of the most surprising political movements in decades, and, historians say, echoing the appeals of some demagogues of the past century.

Mr. Trump’s breezy stage presence makes him all the more effective because he is not as off-putting as those raging men of the past, these experts say.