Ruth Ben-Ghiat is a frequent contributor to CNN Opinion, and professor of history and Italian studies at New York University. Follow her on Twitter: @ruthbenghiat. The opinions expressed in this commentary are solely those of the author.

(CNN) They're an English teacher's nightmare: full of misspellings, typographical and grammatical errors, strange or missing punctuation. Read carefully, they often make no sense. They are full of Weird Capitalizations AND WHY IS HE ALWAYS SHOUTING?

They are tweets from the personal account of President Donald Trump. It's not hard to see why his critics point to his Twitter feed as evidence of instability and unfitness to hold America's highest office: rages, lies, vindictiveness -- it's all there for the world to see, as is dangerous egomania. The tweets cry out: READ ME!

As always with Trump, there is more to the story. We know a lot by now about the content of the President's tweets, thanks to linguists like Jennifer Sclafani and political commentators who analyze them with the care of Cold War-era Kremlinologists.

We know that Trump writes the way he speaks, uses a fourth-grade level of vocabulary and repeats simple phrases that present the world in black and white. People and events are either "great" or "not good," "terrific," or "terrible," depending on how they feel about him and align with his agenda. We know he doesn't bother to correct spelling errors, and often uses the wrong word ("Council" instead of "Counsel" happened -- not for the first time -- this weekend). His goal when he communicates is to persuade -- and often to goad -- not win praise for accuracy.

Yet Twitter is a system of visual as well as verbal communication, and the visual dimension of tweets is highly relevant, given how image-focused Trump is. The way things look is of paramount importance to this man who produced and starred in a reality television show and who relies heavily on television to form his own picture of the world.

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