Study: Presidential candidates speak at grade 6 to 8 level

Researchers at Carnegie Melon University recently analyzed the words used in public speeches by current presidential candidates. The results show most candidates employ language at 6th grade to 8th grade levels, with Republican front-runner Donald Trump speaking at the least advanced level.

While it's likely all of the presidential candidates -- successful and college-educated -- can read and speak at more advanced levels, their public speeches feature relatively simple words and phrases.

Researchers at Carnegie Mellon's Language Technologies Institute used a readability model called REAP to analyze the public speeches of Trump, Ted Cruz and Marco Rubio, as well Democrats Hillary Clinton and Bernie Sanders. Unlike other models, which focus on sentence length and syllables, REAP looks at grade level of commonly used words and grammatical constructs.

"Assessing the readability of campaign speeches is a little tricky because most measures are geared to the written word, yet text is very different from the spoken word," Maxine Eskenazi, LTI principal systems scientist, explained in a press release. "When we speak, we usually use less structured language with shorter sentences."

The results suggest all presidential candidates have simplified their language as the campaign has progressed. The level of language used by both Clinton and Trump varied the most, suggesting the two candidates tailor their words to their audience.

Results of a Carnegie Mellon University readability analysis of speeches by US presidents and presidential candidates. Elliot Schumacher/Carnegie Mellon University

Sanders consistently speaks at higher level than the rest of the candidates, employing 10th grade vocabulary on average.

Historically, President Abraham Lincoln sets the bar. The Gettysburg Address reads well above a 10th grade reading level.

Modern presidents have all used relatively basic language. Ronald Reagan, Bill Clinton, George W. Bush and Barack Obama all used vocabulary of at least an 8th grade level, though President Bush used only a 5th grade level of grammar.