Donald Trump has bragged about having “the best words,” but the Republican presidential nominee’s former ghostwriter says he doesn’t have very many of them.

“He has the smallest vocabulary of any person who has ever run for any kind of office, much less president ― how about county commissioner?” Tony Schwartz said Sunday during an appearance with MSNBC’s Joy-Ann Reid.

Schwartz was the ghostwriter for Trump’s 1987 best-selling The Art of the Deal, and has said he wrote “every word” despite being listed as a co-author. Schwartz has said he worries that the book helped create a falsely positive impression of Trump, so the writer started speaking out against the candidate as his campaign picked up steam.

Schwartz said Trump’s vocabulary is tiny ― evidenced by how he ad-libs his speeches with phrases like “believe me.”

“It’s a 200-word vocabulary, so as soon he gets beyond that, you know that he’s reading someone else’s words,” Schwartz said. He theorized that Trump probably doesn’t familiarize himself with prepared remarks before delivering them because of his “incredibly short attention span.”

While most candidates speak at a sixth- to eighth-grade level, Trump “lags behind others” when it comes to vocabulary and grammar, according to a March analysis by Carnegie Mellon University.

Abraham Lincoln’s grammar sets the bar with an 11th-grade level, while former President George W. Bush’s fifth-grade grammar ranked even lower than Trump’s (although Bush’s vocabulary rates much higher).

Schwartz, who spent 18 months working closely with Trump in the 1980s, noted that the GOP nominee’s limited vocabulary is reflected by his policy positions: The candidate began his run with populist rhetoric, but his current agenda favors the ultra-wealthy.

“I don’t think he knows the word ‘irony,’” Schwartz said. “Irony, nuance, subtlety ... those aren’t part of that small vocabulary.”

Editor’s note: Donald Trump regularly incites political violence and is a serial liar, rampant xenophobe, racist, misogynist and birther who has repeatedly pledged to ban all Muslims — 1.6 billion members of an entire religion — from entering the U.S.