For someone with a passion for written and spoken English, Donald Trump’s vocal communication, with the exception of his prepared speeches, can be a verbal assault. It’s not that Trump produces an overflow of information. Quite the opposite; he often expresses a thin, short thread of coherent thought thoroughly tangled in meaningless idioms and disjointed propositions.

Trump can give an entire interview without speaking in a complete sentence. Once he emits a sufficient amount of verbiage …   well, like that. You should be able to guess what he meant to say by now, he’s had enough, and he’s on to something else. Rhetorically, the tendency might indicate an inability to follow through on the intricacies of a fully-formed idea. It can be amusing, until you realize this person might be signing critical documents with international bodies, documents in which a word out of place can be disastrous.

When faced with a question he either cannot or prefers not to address, Trump tends to run down the clock, and wear down the interviewer, by meandering through an answer. He goes off on tangents, engages in self-promotion, and reverts to catchphrases. Quantity instead of quality; verbiage instead of substance, and almost all of it overly simplistic. All presidential candidates try to phrase their ideas in language that most constituents can grasp. During the primary season almost all leading candidates spoke at levels of sophistication between seventh and eighth grade. Content analysis of Donald Trump’s rhetoric concludes that he speaks at a fourth grade level. Almost all of the words he utters are no more than two syllables.

It is also interesting how Trump appears not to understand some basic idioms. A case in point is the nickname he uses when he ridicules Elizabeth Warren, who has attacked him a number of times. Trump calls Warren, “Pocahontas.”

As the story goes, Warren informed her employers at Harvard that she was of partly native American extraction and chose to be listed as “Native American” under her ethnicity classification. It was also revealed that Warren had no documentary evidence to support that classification. At best, even taking Warren’s word for her own narrative, she is 1/32 native American. And so, she earned the name, “Fauxcahontas,” for her effort to pass as a counterfeit Indian.

Yet Donald Trump calls Warren, “Pocahontas,” apparently oblivious of the Fauxcahontas pun. Given his authoritarian, narcissistic personality and thin skin, one can imagine a collective reluctance among his entourage to set Trump straight on the pun’s nuances. This and Trump’s difficulty with stringing sentences together might be an indication that Donald Trump’s language faculty, more specifically his literacy, may be lacking. There are more.

In a recent New Yorker article, “Donald Trump’s Ghostwriter Tells All,” Jane Mayer interviewed Tony Schwartz, the ghostwriter of Trump’s bestselling book, (at least it’s Trump’s by copyright,) “The Art of the Deal.” The article generated controversy surrounding Schwartz’s narrative of working for and with Trump, and a legally hostile reaction from the Trump camp.

Schwartz described several functional difficulties he experienced while working on the manuscript. Originally intended as an “autobiography” of the then 38 year-old Trump, the project refocused into a business practices manual — of sorts — infused with self-glorifying memoirs. As Schwartz recounts, though, he faced difficult problems concerning Trump’s modes of personal communication and information processing.

One of the most troubling aspects of Trump’s demeanor for Schwartz, and his Trump-centered project, was his observation that Trump had no attention span. This revelation brings new insight into Donald Trump’s performances in the debates as well as his attack mode when dealing with his rivals. During those debates, as well as his numerous interviews and press events, Trump did not address policy issues in-depth. Instead, he reverted, as he does today, to describing policy in the broadest terms, at the abstract level of slogans, and personal attacks. It was no accident that Trump avoided debating Ted Cruz one-on-one, in a setting in which he would not have been able to avoid the challenge of in-depth substance, and where he would not have been able to hide his information deficits.

What are the strategic, political, and governing ramifications of a chief executive with severe attention deficits? The answer is a long list of extremely troubling and dangerous possibilities, from global geopolitics to domestic economics. Although a President of the United States need not keep track of details, he must have the facility to quickly come up to speed on complicated situations which defy simplistic digests. He must have the facility to attend with focused intensity when occasions demand it. When considering the nature of protracted crises and critical events, such as an ongoing terrorist attack or a military  operation, that intensely focused attention must be sustained. The task of informed decision-making in many situations cannot be delegated, not even to cabinet personnel. If Donald Trump has an attention deficit issue, it may constitute a lack of fitness for the office.

A president must also be ready to process verbal information quickly and effectively. In other words, a president must be able to read. Even those who brought into question the intellectual capacities of Ronald Reagan and George W. Bush could not argue with the fact that both were voracious readers. Tony Schwartz’s recollection of Donald Trump, however, reveal an individual who does not read. By Schwartz’s account, Trump “prefers TV as his first news source—information comes in easily digestible sound bites.” The writer commented that he never saw a book near Trump’s working or living quarters. Literacy issues would also explain why Twitter is Trump’s medium of choice. With Twitter’s 140 character limit, Tweeting has its own ad hoc language and low expectations of rhetoric and grammar. It is also the ideal medium for the hit-and-run personal attack.

One would reasonably doubt that Donald Trump is functionally illiterate, given that he completed an advanced level of formal education. Trump’s public speaking shows qualitative improvement when he uses a teleprompter, so his functional literacy isn’t in question. But even so, does Donald Trump have the propensity or, if necessary, the focused willpower to read for deep comprehension rather than a brief recital? Trump clearly has a passionate interest in real estate development and brand marketing (when that brand is “Trump”) but can he patiently sustain attention to problems which don’t fascinate him? And if his patience is so limited, can he function under a system of government with institutional checks on the executive branch, checks that demand a deep understanding of the complex considerations of lawmaking?

Trump’s narcissism prevents him from worrying about whether he has a literacy problem. So, in the event that he becomes president, it’s not his problem; it’s ours. If there is a crisis requiring literacy and/or attention abilities that he lacks, we may all find that his tweeting skills are not nearly enough to pull us through.