Which Words in German are regularly capitalized? Is it just the Nouns? Or are some of the adjectives capitalized? I wish we capitalized all the Nouns in English. It sure would help the Kids recognize a Noun when they saw one.

Just only nouns as a regular course. Other words are situationally capitalized as in English.

But I think this has been an evolutionary process. Aren't all nouns capitalized in, for example, the Declaration of Independence? When did the change occur so that now only Proper Nouns are capitalized?

In the first Sentence the Noun causes is not capitalized. I went a few Items down the List and saw no other uncapitalized Nouns.

Just to split a few hairs, capital letters do rarely appear in some common nouns as I noted somewhere here on AWAD a month or so ago--especially in instances of animal names:

Burchell's zebra
Thompson's gazelle
French poodle

...and so on. There are hundreds of common names of animals in which a capital letter appears although one part of the compound word is always, to my knowledge, in lower case. I think this is worth mentioning simply because it may be a pitfall to think that all common nouns appear in lower case when there are some exceptions floating out there in dictionaries, particularly unabridged and technical dictionaries. Even more interesting, I think, is how a common noun picks up what some might think of as a word functioning as an adjective, when, in fact, the word transmutes into a compound noun--and is identified as such in dictionaries. I would love to know what linguists make of the deep structures of such nouns. Does the adjectival sense just fly out of the window in the case of, for instance, German shepherd? I would think definitely so. There is no shepherd here (dog = shepherd)--and we don't somehow modify this non-existent shepherd with 'German'--and voila!--there's a dog. The whole noun unit is 'German shepherd'; common noun; specific type of dog feared by many, but gloriously strong, fast and smart!

Even with Thompson's gazelle I would argue that there isn't this standard gazelle that we somehow modify with Thompson who found a distinct species. We just happen to have to separate this species by the person who identified it--and we don't want to reduce poor Thompson to a lower case 't' just to keep our common nouns thoroughly without capital letters.

I find all of this fascinating, somehow, so please excuse my bloviating upon the point.