You forgot that a linguist analyzed that speech and concluded that it was natural casual speech.
https://archive.ph/PJcMgWhat Trump’s Speech Says About His Mental Fitness
By JOHN MCWHORTER
"As part of the discussion about Donald Trump’s lack of fitness for the presidency, some have argued that his linguistic capacities have worsened, suggesting significant cognitive decline.
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Casual speech tends towards the repetitious, as we seek to indicate sincerity and make sure our meaning has gotten across. Mr. Trump, because he speaks casually, does a lot of repeating....
Real speech tends to be fundamentally subjective rather than objective, and is therefore decorated with what linguists call pragmatic words and constructions, expressing attitude rather than content...
This passage also has a kind of coherence. Mr. Trump starts out addressing the nuclear deal with Iran, but then interjects some insights about his elevated qualifications for discussing the subject and his resentment of a purportedly biased media that forces him to mention them – and then he does get back to the nuclear subject. Elegant? No, but not demented, either. Facial expression and context, which print obscures, made Mr. Trump’s meaning clear.
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The difference between the younger man talking in sentences and the older one talking in vocal ejaculations is evidence not of decline but authenticity – he has settled into his normal. Late in life an artless man has learned that he could leave his linguistic fly unzipped and life would go on. It may not be pretty, but it isn't a sign that his pants are going to fall down.
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John McWhorter is a linguist, an associate professor of English and comparative literature at Columbia, the author of books like “Words on the Move,” and host of Slate’s language podcast “Lexicon Valley.”