These days, presidential candidates are speaking at a lower reading level than many did in the past. 

Carnegie Mellon University's Language Technologies Institute (LTI) did an analysis of speeches by presidential candidates, learning that while most of them used grammar and words that ranked as typical for students in grades 6-8, Donald Trump's speech lagged behind others. 

LTI conducted a historical review of word and grammar use by five candidates, finding that it's likely that Trump, Ted Cruz and Marco Rubio (who is no longer running), and Hillary Clinton and Bernie Sanders are all using simpler words and grammar constructs as the campaigns move forward. Trump's language use is following a less predictable pattern, with grammar complexity spiking in his concession speech for the Iowa Caucus and grammar and word use falling heavily in his victory speech for the Nevada Caucus. 

His Iowa concession speech used the word "regrettably" - and yes, it is less likely to show up in a third-grade textbook than "win," which dotted his Nevada talk. 

A look at previous presidents ranked President Abraham Lincoln highest, with 11th grade level grammar, and President George W. Bush pulling down the average with fifth grade grammar below even Trump's typical usage. 

"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," noted Maxine Eskenazi, principal systems scientist at LTI. She and  Elliot Schumacher, a language technologies graduate student, performed the analysis. "When we speak, we usually use less structured language with shorter sentences."

An earlier analysis by the Boston Globe used the Flesch-Kincaid readability test, which is based on average sentence length and average number of syllables per word, and found Trump speaking at a fourth grade level, two grade levels below his peers. Eskenazi and Schumacher used a readability model called REAP, which looks at how often words and grammatical constructs are used at each grade level and thus corresponds better to analysis of spoken language.

Vocabulary analysis placed campaign trail speeches by Lincoln, Ronald Reagan, Bill Clinton, Barack Obama and George W. Bush at least on an eighth grade level. But in the present day, there was a wide range, from Trump at the seventh grade level to Sanders at a 10th grade level. Trump and Hillary Clinton may endeavor more to customize speeches for specific audiences, based on the fact that their speeches revealed the widest variation in the study, said Schumacher. 

Lincoln's Gettysburg Address, a high standard, had grammar at above the 10th grade level in the analysis. The study is available online. 

Follow Catherine Arnold on Twitter at @TreesWhales.