(The following notes have been deduced from the German versions of Terranigma and The Legend of Zelda: Ocarina of Time. Unfortunately, I didn't document my findings as closely as I am now, so some of what I have figured out is a bit sketchy.)
I can't exactly explain how I figured out the sentence structure and most of the important words in any German sentence that appears quite frequently--most of the time, they're in sentences where characters introduce themselves, or they are similar to or are roots of English words as well. For example, "Pfeife" is the root word of "fife" and "Diebe" is the root word of "theif". It is also easier to pick off words from shorter sentences.
unsterblichkeit = immortality --> un-, sterben, -lich, k/heit
Geheimnis = secret --> ge-, Heim, -nis
grunsamkeit = rudeness --> grunsam, -k/heit
weitgereister (don't know exact definition; something like an experienced traveller) --> weit, ge-, reisen, -er
Kraft = power, as in Kraftpunkte (for HP) but plural seems to be kräfte
-kennen has similar meaning to weißen, but in all cases of usage, usually refers to knowing a person.
Erfolg -- could this mean success? The root is the verb, folgen, to follow.
wirklich = really; wirklichkeit = reality
ändern = to change (or see verändern); found the 3rd person singular to be ändert (with umlaut)
"would" or some other tense auxiliary verb: wird, wirst-- have not identified the infinitive form yet. The first is a 3rd person singular, and the second is 2nd singular.
schaffen = to create (the opposite, zerstörten, to destroy)
Geschichten = history (is this used in plural? Have forgotten what the singular form might be)
Ich versuchte die *mächtigen Mondsteine zu finden.
I tried to find the Moonstones.
*could this adjective be "majestic" or related in meaning?
I have seen bitte used to mean please. But what about a verb? Have seen "Ich bitte..."
Großartig! --> "Great!"
brauchen --> does this mean "to need"?
Du brauchst nicht zu sagen.
"You need to say nothing."
Ich brauche gerade nichts.
"I need nothing..." (I have not figured out what gerade means...)
Wir brauchen Hilfe.
"We need help."
Seems as if these examples point towards it.
Wie grausam ist doch das Leben...
How cruel is (but) that life... (Note: I have often seen "doch" inserted into sentences like this.) (I supposed grausam is cruel, since I have already figured out what "Leben" is.)
In Zeiten wie diesen Muß ein Mann Starke zeigen!
In times like these, a man must show strength! (Note: "Zeiten" seems to be plural for "Zeit". Then another example indicates zeigen is most likely the verb for "show": Zeig ihn mir! --> "Show it to me!")
Einer allein ist schwach, doch gemeinsam sind wir stark.
Alone, one is weak, but together, we are strong.
(It seems gemeinsam is another way of saying "together"; I may have seem "zusammen" used the same way; will need more examples. And here, we see schwach = weak.)
Claim: the imperative is the verb stem. This is true in most sentences, except some exceptions: Spiele die Melodien... --> Play the melody, or Höre... "Hear...". Will try to find more examples.
Sag uns, wenn du nette Dorfer und Stade findest.
Tell us if you find nice towns or cities. (Sagen can be used as "tell" in imperative. I'm not sure if Dorfer or Stade refer to towns or cities; just places where people live.)
UPDATE: it seems Dorf has more commonly been associated with village in other examples. Stadt may still mean city or town.
war --> past tense, 1st, s
warst --> past tense, 2nd, s
wart --> past tense, 3rd, s (I guess...) Will need more examples on plural forms. I'm fairly sure these are past tenses.
Es scheint von dem Tisch dort in der Ecke zu kommen.
It appears to come from the desk in the corner. (I think Ecke is corner; I have not figured out what exactly "dort" means.)
UPDATE: Another example has confirmed that "Ecke" is corner.
Is it hilfen or helfen? In almost all cases, it appears as some form of "helf-", but an example says "Hilfe...Bitte hilf mir."
Lass den Knopf los!
Let the button go! (another interesting usage of the word, "los" for "go")
CLAIM: add -den after the infinitive for the gerund. --> Ein Kelch soll die Trinkenden den Göttern nahebringen.
for participles, I have seen both -d and -de--> arbeitende
Ein Löwe! Ein Löwe jagt mich.
A lion! A lion is chasing me.
The "I wonder..." construction: Ich frage mich, or literally, "I ask myself..." for other constructions, just change the person to 2nd or 3rd accordingly (he asks himself, they ask themselves, etc.)
Sie hat mich aufgemuntert und mir Mut gemacht, nicht aufzugehen.
The original translation in English is written as: "It would cheer me up saying light will shine on if I live on." But the last part says "...and gives me courage not to give up." (well, I'm not really sure about that last part; I made an educated guess. It seems the construction for giving courage requires the use of the make/do verb.)
Rettungsteams --> probably "Rescue team"; root from retten.
Anhänger --> "pendant"; Ich weiß es. Nimm deshalb diesen Anhänger.
I know it. Take this pendant. (I cannot, for the life of me, figure out what deshalb means. I will eventually. Mark my words, I will.)
Mädchen --> girl
(I wondered about this for awhile; but then several more examples seemed to indicate that was so; Kannst Du das Mädchen beschützen? --> Can you protect this girl? (Now why is "Du" capitalized? I thought pronouns weren't supposed to be. There might be a stylistic reason for this I'm not aware of. Otherwise, it's just a stray grammar error.)
Von hier aus will ich Zeuge des Weltuntergangs sein.
From off (of) here, I will be witness of the end of the world. (I guess welt + unter + gangs somehow refers to the end of the world; using the process of elimination and the script, that's the only thing it amounts to. Other examples show that "Zeuge" is quite likely to mean a witness.)
Das sind meine Gedanken.
Those are my thoughts. (That's what the context seems to imply. But Gedanken looks more like it came from dank for thanks.)
Die Leute denken nur an heute, niemand denkt an morgen.
The people think only about today, but never about tomorrow. (well, the script said tomorrow, but morgen means morning. Could that really be the "tomorrow" I'm looking for?)
Viele Menschen ließen ihr Leben im heißen Sand.
Many people lose their lives in the hot sand. (the script said "harsh" rather than hot; I'm not sure if heißen can mean harsh.)
nie - a negation used with mals and mand; (never, no one). By itself, I've seen it can mean "never". If there's a distinction between using either nie or niemals, I haven't figured it out.
je- or jede; every, all; with -mand, it means anyone, someone or maybe everyone.
Wie kommt er also hierher? (another interesting usage of "wie", which I've seen to mean "like" as well; in this case, it's just How come... as it is in English.)
Kelch; goblet; plural is Kelchen
allein = alone; another similar word: einsam --> lonely; now add "keit" and you get loneliness. (it seems the h in "heit" after an "m" is also changed to a k.)
schau - look
Menschen sind sehr pathetisch.
People are very pathetic. (in the script, it says Humans are pathetic creatures.)
wunschen = to wish; Wünschen is the noun form; wishes, desires.
verschwindeln - to lie, swindle
verschwinden - to disappear
erscheinen - to appear (compare schein, to appear for more abstract usage)
Ich mache Dich zum Gott...Zum Todesgott!
I'm going to make you into a god...(into) a death god! (another example where a pronoun is capitalized...)
Bevor ich die Welt verlaße, will ich Dir etwas öffenbaren.
Before I leave this world, I will offer you something. (that's where I was convinced offenbaren means offer. And bevor is before.)
Niemand wird es verstehen.
No one would understand it. (another of those strange verbs. Wirst is the 2nd person singular.)
Du wurdest nur benutzt...
You were only used...
Das Ende des Lebens ist banal.
The end of life is trite. (where I find that banal is trite, since I know the meaning of every other word.)
Grabstein = Tombstone
Weißt Du warum? Weil Du der legendäre Held bist...
Do you know why? Because you are the legendary hero... (Well, the script says "because", but I'm not sure if "weil" means because. I don't see this very often.)
stören = to disturb (compare with zerstören)
Vermaledeit = ? I can't find this word! It appeared 3 times! (Well, in the English translation, it was used in place of "Shoot!")
Zeigen --> Zeiger; to point--> pointer (eg, on a clock)
Ich bin supersauer.
I'm going to sulk. (that was in the script.)
Teufel = devil
Benutzen = to use --> nutzlich --> useful; nutzlos --> useless
fur immer --> forever, perhaps?
immer --> seems to be always... (these words always take the longest to figure out because they could be anything.)
Lebewesen = living things (I found this out much before this sentence:)
Doch ich bin ein Wesen aus Fleisch und Blut...
But I am a being of flesh and blood... (so I implied the wesen in Lebewesen and that sentence.)
die Lady mit dem Schwert.
(Does German not have a word for swordswoman? With so many compounds, there ought to be one...)
Enkelin --> granddaughter, perhaps? (I only saw it once.)
durch --> seems to mean "through".
unheimlich --> uncomfortable, scary; un-, heim, -lich
unmöglich --> impossible; un-, moglich
unglaublich --> unbelievable; un-, glauben, -lich
Doppelganger (saw this in two separate games; one was actually the name of the character in English; so I suppose "Doppel" is double.)
Genieße deshalb Diene letzten Tage...
Enjoy your last day... (I suppose Genieße is enjoy. I can't see what else it would be, since I have not seen "deshalb" in any other form.)
(un)wichtig = (un)necessary or (un)important.
bald = soon