If it's a masculine or a neuter noun, then
s is usually added to the noun when it's genitive. Some masculine nouns, eg.
Junge don't follow this rule. http://canoo.net/inflection/junge:N:M:boy
Plural dative: an
en is added, eg.
die Geschwister (nom, acc plural), but
den Geschwistern (dat plural) http://canoo.net/inflection/geschwister:N:N
You leave grave accent symbols (`, left of the 1 key on most American keyboards) around the text:
whenever I think I start to get German and know the rules something like this comes along and I realize... nope...
Always like that, man. Especially regarding Akk, Dat, Gen... Sad, but true. ='(
I was just searching, this handout seems to be really informative, and your question was mine, exactly. I bookmarked this http://www.nthuleen.com/teach/grammar/genitivexpl.html
In Portuguese we say "dona de casa" (owner/ruler of house) to refer to a woman whose sole or primary activity would be taking care of her household. Does "Dame des Hauses" have the same meaning?
Is there a particular reason why "That's the house's lady" is not acceptable? I guess it sounds funny, but it seems correct...
in english "lady of the house" is an expression which cannot be replaced by "the house's lady". So its not the grammar but common usage that requires this form.
It is not incorrect but would not usually be used by an English speaker. Matron is generally used for a female medical supervisor in day to day speech..
Why use one of the few examples in English that typically demands the more formal-sounding structure (e.g. "of the house," rather than "house's lady.")! Duolingo's lesson on Genitive suggests that you can say "Das ist die Dame von dem Haus." but that it sounds stilted. Funny that this is one example in English when "the noun of the noun" is preferable to "the noun's noun"!
what case is 'die dame' acc. or dat. (sorry this is probably a really dumb question)
Nominative, actually. "Is" is a linking verb, so whatever's after it is in the nominative to match the nominative before it. (A tricky concept, but it's the same reason grammar traditionalists will tell you to say "It is I" instead of "It is me.")
You can pretty much just remember that whatever comes after the verb "sein" is in the nominative, rather than the accusative like most verbs would use.
No such thing as a dumb question, because you obviously know something (accusative and dative, for example) in order to ask it! :-)