“No president has ever spoken like that before,” President Joe Biden said of former President Donald Trump during their June 27, 2024, debate. He was referring to Trump’s suggestion of seeking political retribution, a part of the projected image that won Trump the Republican nomination and presidency in 2016 – one that is on display again in the current presidential election campaign.

A UCLA working paper, “Donald Trump’s Words,” explores the distinctiveness of the Republican presidential nominee’s rhetoric and places it in a broader historical perspective. The study, published by the National Bureau of Economic Research, is co-authored by UCLA department of political science graduate student Nikita Savin and Daniel Treisman, a UCLA political science professor and a research associate with NBER.

Savin and Treisman analyzed transcripts of 99 Trump speeches from April 2015 to June 2024 — focusing on political rallies and mass meetings aimed at the general public and speeches to political parties, political conferences and labor unions — then compared them to speeches made by other major politicians past and present, including all American main party presidential candidates since 2008, and foreign dictators. Sourced from online archives and transcripts, Trump’s vocabulary in these speeches was also compared with political rhetoric dictionaries that categorize words based on their usage in sample texts (such as prosecutors’ closing arguments in war crimes and budget speeches of finance ministers).

From this, the study found an increased use of violent language over time and a sharp decline in references to economic performance. The authors identified a form of  “negative populism” in Trump’s speeches, exemplified by the frequent use of the pronoun “they” and a rise in pejorative terms for elites. Although dictionary-based text analysis only measures the frequency of words without delving deeper into their contexts, it is effective at identifying patterns.

“We know from past research that inflammatory rhetoric can prompt a few unstable individuals to engage in political violence,” Treisman said. “Given that, it’s important to carefully monitor the speech of radical populists like Trump.”

Violent vocabulary

Violent language in the study is not the same as calls for violence, but rather involves the use of words with a violent connotation and various violent subjects.

The co-authors searched political speeches for a list of 142 keywords, based on a 2019 dictionary compiled by Treisman and former European Bank for Reconstruction and Development chief economist Sergei Guriev, to study differences in rhetoric among the leaders of different types of political regimes.

Trump’s use of violent language has increased over time and is now at a higher level than any other U.S. major party presidential candidate since 2008. Trump’s use of violent language includes references to crime and war, as well as other contexts such as immigration and even shark attacks.

Citing past studies, Savin and Treisman write that this type of vocabulary can have a range of effects on listeners with aggressive personalities, including motivating them to vote and boosting support for violence among subjects with aggressive personalities. Scholars have documented increases in hate crimes after Trump’s campaign rallies and tweets. The authors suggest that Trump utilizes violent language to spread fear and anxiety, fueling demand for a strong leader who can defend against dangerous threats.

Despite being president during the start of two foreign wars and other ongoing conflicts abroad, Biden’s use of violent vocabulary during both the 2020 and 2024 presidential campaigns was consistently less than Trump’s. Hillary Clinton’s use of violent words in her 2015-2016 campaign slightly exceeded Trump’s relatively moderate level at that time, which could reflect Clinton’s desire to show “toughness” given stereotypes of women leaders being less hawkish, the researchers wrote.

Trump’s speeches at his most recent rallies in 2023 and 2024 have employed the most violent language of his political career and were only marginally less violent on average than Cuban dictator Fidel Castro’s May Day speeches from 1966 to 2006, according to the researchers.

Economic performance and public service provision

The study also found a decrease in references to economic performance in the speeches of all presidential candidates since 2012. That might be because, as UCLA political science professor Lynn Vavreck has shown in other work, all insurgent candidates since 1952 who ran on the economy have lost.

Trump also refers relatively infrequently to public services like education and health care. In contrast, Democratic candidates have consistently mentioned public services more often than Republicans, except for a brief period in 2023 when Biden discussed them sparingly.

Populist discourse

Most strikingly, the study found that Trump has been effective in creating his own brand of negative populism through his rhetoric. While traditional right-wing populism frequently utilizes “us” against “them” language, it balances the opposition to elites with a more inclusive rhetoric about “the people.” Trump, by contrast, refers to “the people” less often than any other recent major party presidential candidate. While using “us” at a roughly average rate, he stands out for his frequent references to “them,” which he has used to target out-groups like immigrants and the unpopular elites, such as “the corrupt globalist establishment.”

The trajectory of Trump’s rhetoric has changed significantly over time. During his first presidential campaign from 2015 to 2016, he embraced a positive populism, increasing references to “the people,” and using “us” more and “them” less over time. But since his first election in 2016, Trump’s uses of “the people” and “us” have steadily declined, while recently his pejorative references to elites have increased. Overall Trump’s speeches contain stronger markers of populism than those of any other presidential candidate that the authors studied except Bernie Sanders.

Trump’s language has also been documented to be simpler, more derogatory and less analytical than American politicians who came before him.

“How Trump’s vocabulary will evolve in the coming months remains to be seen,” Treisman said. “But the rising temperature of his rhetoric bears watching.