The first letter of the word. Haus, not HAUS.

he uses initial caps more often. Here's an example, in his Truth Social post about MTG:

"I am withdrawing my support and Endorsement of "Congresswoman" Marjorie Taylor Greene, of the Great State of Georgia. Over the past few weeks, despite my creating Record Achievements for our Country including, a Total and Complete Victory on the Shutdown, Closed Borders, Low Taxes, No Men in Women's Sports or Transgender for Everyone, ending DEl, stopping Biden's Record Setting Inflation, Biggest Regulation Cuts in History, stopping EIGHT WARS, rebuilding our Military, being RESPECTED by every Country in the World (as opposed to being the laughingstock that we were just 12 months ago!), having Trillions of Dollars (Record Setting!) INVESTED in the U.S.A., and having created the "HOTTEST" Country anywhere in the World from being a DEAD Country just 12 months ago (and so much more!), all I see "Wacky" Marjorie do is COMPLAIN, COMPLAIN, COMPLAIN! It seemed to all begin when I sent her a Poll stating that she should not run for Senator, or Governor, she was at 12%, and didn't have a chance (unless, of course, she had my Endorsement — which she wasn't about to get!). She has told many people that she is upset that I don't return her phone calls anymore, but with 219 Congressmen/women, 53 U.S. Senators, 24 Cabinet Members, almost 200 Countries, and an otherwise normal life to lead, I can't take a ranting Lunatic's call every day. I understand that wonderful, Conservative people are thinking about primarying Marjorie in her District of Georgia, that they too are fed up with her and her antics and, if the right person runs, they will have my Complete and Unyielding Support. She has gone Far Left, even doing The View, with their Low IQ Republican hating Anchors. Thank you for your attention to this matter. MAKE AMERICA GREAT
AGAIN!"

Assuming he knows or cares.
You don't capitalize adjectives. Just nouns.
English. German cars.
German. german Cars. deutschen Autos.

I don't think he even has a clue.

He doesn't understand English capitalization, either. He just does as he pleases, "fuck the world...."

If I think about it, I can hear the inflection in my mind before I speak it. When I vocalize my thoughts, I convert my speech pattern to a Western European sound.

For the most part, my default inflection does not foster emphasis on words in a sentence. I avoid typing in caps partly because it is not a natural voice inflection for me.

I am not sure why Trump has a penchant for typing in upper case. Maybe it is just a matter of his bullying nature rising to the surface.

He knows no languages other than English, and he is neither a good speaker or writer in that language, either. A poor communicator, he uses verbal emphasis in unorthodox ways, as well.

He shouts. He yells. He speaks emphatically, even if he has little to say. He's a small man trying to look as large as possible.

When you capitalize everything, you don’t have to know the rules; you can cover for your ignorance of the written English language.

He is ignorant and impatient.

I think it is as simple as that.

The logical explanation is that he simply doesn't excel at English grammar. He's a very stupid man.

have more to do with the fact that he's writing the way he thinks (which is shouty and incoherent). He wants us to know that some things are VERY IMPORTANT, and since capitalizing words is the only way you can yell on the Internet, he does it by using all-caps. As well as SHOUTING, he capitalizes the first letter of some words, adjectives as well as nouns, that he wants to emphasize. But although this gives his rants a bit of a Führer vibe it's not so much Germanic as illiterate. You read his social media posts and figure they came from an angry teenager with oppositional-defiant disorder posting from his parents' basement, furious because they're turning off the wi-fi at 10:00 pm so he can't look at porn all night.

Occasionally Trump writes something that might work in Fraktur, though. Maybe he should persuade his Fake Twitter techies to give him that option.

Thanks!

discovering common words like "groceries"? He builds a scaffolding of verbiage, probably with help, and constantly repeats it until it becomes a "patter" that he can blurt out for any occasion.

His childish use of "Thank you for your attention to this matter," is worthy of a bill collector and not much else.