If you've never tried to punctuate/interpret a Donald Trump sentence in writing, you haven't lived. I took a whack at a questionable formulation here:

"There is no collusion between certainly myself and my campaign—but I can always speak for myself and the Russians, zero," [Trump] said during a joint press conference with Colombian President Juan Manuel Santos.

On paper that quote looks a little muddy, but to the ear it was clear that he meant he could "only" speak for himself. In other words, I can't defend what the rest of my campaign did, nor will I.

Apparently, I'm not the only one who's found Trump syntax challenging. STAT fixated on the very same sentence in a piece examining Trump's declining linguistic capabilities over the past couple decades, and it's quite revealing, writes Sharon Begley:

In interviews Trump gave in the 1980s and 1990s (with Tom Brokaw, David Letterman, Oprah Winfrey, Charlie Rose, and others), he spoke articulately, used sophisticated vocabulary, inserted dependent clauses into his sentences without losing his train of thought, and strung together sentences into a polished paragraph, which — and this is no mean feat — would have scanned just fine in print. This was so even when reporters asked tough questions about, for instance, his divorce, his brush with bankruptcy, and why he doesn’t build housing for working-class Americans.

Trump fluently peppered his answers with words and phrases such as “subsided,” “inclination,” “discredited,” “sparring session,” and “a certain innate intelligence.” He tossed off well-turned sentences such as, “It could have been a contentious route,” and, “These are the only casinos in the United States that are so rated.” He even offered thoughtful, articulate aphorisms: “If you get into what’s missing, you don’t appreciate what you have,” and, “Adversity is a very funny thing.”

For instance, check out Trump talking poverty in 1987—suggesting that you “really need the federal government to step in” to offer assistance to America’s poor and disenfranchised. He even uses whole sentences. Of course, it’s consistent with modern-day Trump in the sense that he lays the responsibility somewhere other than on his own doorstep.

The linguistic experts at STAT offered different explanations for the obvious difference over the decades and all agreed that without specific testing, they couldn't be sure about the cause of the variation.

John Montgomery, a psychologist in New York City and adjunct professor at New York University, said “it’s hard to say definitively without rigorous testing” of Trump’s speaking patterns, “but I think it’s pretty safe to say that Trump has had significant cognitive decline over the years.”

No one observing Trump from afar, though, can tell whether that’s “an indication of dementia, of normal cognitive decline that many people experience as they age, or whether it’s due to other factors” such as stress and emotional upheaval, said Montgomery, who is not a Trump supporter.

Whatever the cause, Trump isn't functioning on the same level he once did, and now he's leader of the free world. Perfect.