Ich habe viele Hilfen über Deutsch in Internetforen bekommen.
Besser: Ich habe viele Hilfen über das Deutsche
in Internetforen bekommen.
No "dense grammatical rule" here, I do in fact have no idea why
it is "das Deutsche" in this case (but it definitely is).
Man benutzet kein Komma vor dem Konjunktion.
Man benutzt kein Komma vor der
Konjunktion ist feminin, deshalb muss man es so sagen. Nur ein kleiner Fehler.
(How would I say "German people"? deutsche leute? Deutscher? deutsche man? Just Deutsche?)
If you refer to all the Germans, you'd say "die Deutschen". If you refer to one German, you'd say "ein Deutscher". It's as easy as that.
Ich würde sagen, "Deutsche Präpositionen sind interessant," "Dieses Buch ist wichtig," und "Das Film war fantastisch!"
Film war fantastisch!
("Film" ist maskulin)
Ja, ist alles richtig.
However, I can say "Das ist mir zu schwer" or "Das ist zu schwer." Does including mir emphasize how it is a personal opinion, and not including it just casual speech?
Ich verstehe das Benutzen des Verb "fällt" nicht.
Ich verstehe nicht, das Benutzen des Verb "fällt".
-> Ich verstehe die Benutzung
"Benutzen" describes more the action of using something, where "Benutzung" is the usage itself. Thus you have to use the latter here.
"Verb" -> "Verbes" because you didn't form the Genitiv correctly.
Mein Wörterbuch sagt, dass "fallen bedeutet fall, go down, be killed in war, drop, make." These words don't make sense, in the context of "Obwohl dir das Deutschsprechen sehr schwer fällt, versuchst du, es zu üben." Is it a figurative use, and if so, which meaning (fall, drop, make, etc.) is being used figuratively?
Yes, it is kind of figuratively. My dictionary says you can use "to drop hints" in English as well, and this is about the meaning it has in German here, "eine Bemerkung fallen lassen" = "eine Bemerkung machen".
Ich mag Katze, weil sie mir nett sind.
-> Ich mag Katzen
, weil sie nett sind.
"mir" again! Just leave it unless you _really_ need it in a sentence.
Außerdem mag ich meine Freunde, weil sie mir auch nett sind.
-> Außerdem mag ich meine Freunde, weil auch sie nett sind.
You have to exchange the words "auch" and "sie" as you mean something else if you express it as you did.
"Sie sind auch nett" means "They are nice as well" (they have many traits, and their niceness is one of them).
"Auch sie sind nett" means "These are nice, too." (many people are nice, and my friends are some of them).
This is a little hard to explain, as in English "They are nice as well" and "These are nice, too" are still not really distinguishable without context. German is a little more strict here.
Warum benutzest du "dafür," und warum benutzest du a subordinate clause (dass) here?
"Dafür, dass <subordinate clause>, <main clause>" is a grammatical construct which expresses that <main clause> even though
<subordinate clause>. There is no particular reason why "dafür" and "dass" are used to express this, because this simply is what they mean in this context. It is also a little hard to translate to English, "even though" is probably not correct. Is "for that" not also possible in English? Im not sure, my English skill reaches its limit here, I guess. So, if "For that you don't learn German for long, you speak very well" is proper English, it also is the proper translation for the sentence in question.
(Ja means yes, but can I also use it as a particle meaning, right? If so, is that usage odd or normal?
Odd. In fact, it sounds kind of aggressive, as if you weren't even expecting an answer ("Either you do this or I cut off your balls. We do understand each other, right?" would be the first sentence to come to my mind...). You better use "..., oder?" or the super-colloquial, ugly and yet extremly widely used "..., ne?". (In some regions, "..., gell?" is even more widely used, but I think it sounds stupid, which is probably because I don't live in these regions.)
ninja'd, but who cares...