Unfortunately, the forensic linguists whom I spoke to in December haven’t yet worked out a model to help determine when Trump might be dictating his tweets and when they come from his very own thumbs. But his use of the word like is still worthy of some armchair analysis.

The commas around like are an anomaly in the president’s tweeting history: Of the tens of thousands of tweets in the Trump Twitter archive, this is the first time like has appeared this way, except for in two manual retweets. One was from a follower in 2013 who, upon hearing that Trump was speaking at the CPAC conference, exclaimed, “This conference just became, like, a hundred times more awesome!” The other, from 2014, was from Peter King of Sports Illustrated, who tweeted, “Why do baseball players slide headfirst? Are they just, like, not smart?” (Trump thought that was a “great point.”)

But while tweeting-Trump may never have used like in this way before yesterday, speaking-Trump uses it all the time—at least when he’s touting his own intelligence. Back on July 11, 2015, less than a month after Trump declared that he was running for president, he told a rally in Phoenix, Arizona, “I’m, like, a really smart person.” (That inspired MSNBC’s Rachel Maddow to run a segment with “Like, a Really Smart Person!” displayed on the screen behind her.) In December 2015, he told CNN’s Don Lemon, “But I’m, like, a really smart person. You know, I went to Ivy League schools.”

He continued the “like, smart” theme all through 2016. “I’m conservative, folks, but I’m also, like, smart,” he said at an Arizona rally in March excoriating Jeb Bush. “I’m, like, a really smart person, like a lot of you people,” he said in Connecticut in April, before explaining that “it’s very easy to be presidential” if he wants to be. And in December, responding to a question from Chris Wallace on Fox News Sunday about why as president-elect Trump was eschewing the daily intelligence briefing, he said, “you know, I’m, like, a smart person.” That led Seth Meyers to crack on his late-night show that “‘I’m, like, a smart person’ is a sentence that disproves itself. It’s like getting a back tattoo that says ‘I make good decisions.’” Despite the ribbing, Trump doubled down when he spoke at the CIA headquarters on his first official day in office, saying, “Trust me, I’m, like, a smart person.”

So this is clearly a thing for Trump, even if it’s only now carrying over to his Twitter feed. Why, we may ask, does this self-declared “very stable genius” keep doing it?

First, let’s consider the role of like in “I’m, like, really smart.” The word like serves a number of functions in casual American speech, all of which tend to be stigmatized—just as Seth Meyers implied—as not exactly sounding “smart.” Alexandra D’Arcy, a sociolinguist at the University of Victoria, takes issue with many of the common characterizations of like that have been attached to it ever since it became associated with beatnik types (think Bob Denver as Maynard G. Krebs on the old Dobie Gillis show), and then with hippies, stoners, and surfers. Later, it was taken as typical of young women, particularly fitting the “Valley Girl” stereotype. (Indeed, many commenters on Trump’s tweet said his “like” made him sound like a Valley Girl.)