I'm afraid that if I try explaining about the definite articles and their different meanings (that, this, etc), I'm going to get more things wrong than right. All I can offer is some hopefully illuminating factoids.

I don't know if you know, the English definite article is derived from the word for "that". In fact, I'm pretty sure the ancestral Germanic language had neither definite nor indefinite articles. In fact it seems to be a secondary development in most European languages. People just kept referring to "those" objects so much that it became a permanent structure. In English it kind of lost all of its explicit meaning (in the way that, for example, it's usually just not translated into article-less languages). In German some of it remains. I mean, a lot. Or you could say, German hasn't acquired a separate word for "that". Although it has a word for "this" - "dieser/diese/dies". I don't know if all that is making sense. I'm just winging it here.

So I think if you try replacing all those definite articles in your speech with "that", you might develop some sympathy for that German way.