I can't for the life of me figure out how to say "which" in this context:
I'm trying to say "The first and second stanzas have different rhythms, which sets them apart from each other..."
I think you should not focus on how to translate an isolated word ("which"), but rather on how to translate the idea. This is how I would express it (a suggestion):
"Die erste und zweite Strophe unterscheiden sich dadurch, dass sie verschiedene Rhythmen aufweisen."
or, shorter and closer to your "set apart" ("sich voneinander abheben"):
"Die erste und zweite Strophe heben sich durch ihre verschiedenen Rhythmen voneinander ab".
"Die erste und zweite Strophe haben (ein verschiedenes Versmaß?*), was sie voneinander unterscheidet."
"was" in this case means "which" in the sense of "which is the thing that [sets them apart]".
(...as opposed to e.g. "The book which I read last week" = "Das Buch, das ich gestern gelesen habe", or also - formally and/or old-fashioned - "Das Buch, welches ich gestern gelesen habe")
*Versmaß = metre / metric pattern, like da-DAM-da-DAM-da-DAM vs. da-da-DAM-da-DAM-da-da-DAM, if that's what you're aiming at?
Well, keep in mind that we could also say " The first and second stanzas have different rhythms, that sets them apart from each other...." http://context.reverso.net/translation/english-german/...different+rhythms%2C+that+sets+them+apart+from+each+other The examples here don't highlight "die" for "that" though they should from what I learned later.
Here are some excellent examples of sentences with dependent clauses: https://www.thoughtco.com/german-sentences-in-the-right-order-4068769
Anyway, I think that I would go with "dass", but I would love to hear from a German speaker.
Ah, here is what I was looking for: http://www.dartmouth.edu/~deutsch/Grammatik/WordOrder/relatives.html
So welcher can only be used for the genitive case. It is after all not a stand alone pronoun, but used more like an adjective, while "which" can be used as a relative pronoun.
So since "rhythms" is plural, "die" ( Accusative would stay the same, but dative would be denen.) I actually bothered to check what gender "rhythm" is : http://dictionary.reverso.net/english-german/rhythms Knowing it is masculine would have been important if it were singular.
See how that is different from "dass" which is a conjunction but not a relative pronoun, http://dictionary.reverso.net/german-english/dass
So from the context link, I learned that "from each other" is "voneinander". I am going to try: "Die erste und die zweite Strophe haben verscheidene Rhythmen, die sie voneinander unterscheiden."
or do I need to use "sich" instead of "sie" ? Sometimes these verbs require reflexive for a particular meaning. I am not sure if this does?