Shoudn't this be 'I listen, therefore/so/consequently she speaks'? If it meant 'because' in this context, why have they not used the word 'foratt' or 'eftersom'?
Are there certain cases when 'därför att' is more appropriate than 'eftersom,' and vice versa?
They are almost drop in replacements for each other. However, eftersom is strongly prefered when in the case where it is the first word in a sentence.
I wrote a super long explanation about this on the reverse sentence forum just yesterday, here: https://www.duolingo.com/comment/5678209 Take a look and see if it helps. At the moment, that comment is at the bottom of the page, it starts with This sentence consists of two clauses. (read the comment I'm answering first)
Yes, but you must reverse the word order in order to make the sentence valid. But you got the idea,
Eftersom hon pratar lyssnar jag means the same and is strongly prefered over Därför att hon pratar lyssnar jag.
I listen, therefore she speaks would be Jag lyssnar, därför talar hon. So notice that därför and därför att function pretty differently.
I think we learned "talar" is also "speak," so is there any difference between talar and pratar in terms of usage, like talar is for only speaking a language and prater is for more general usage, kind of like the difference between "parler" and "dire" in French?
They are pretty much drop-in replacements for each other. Talar is more common in writing and in formal language whereas pratar is more common when speaking.
That's kind of funny you say that as I've been associating the word "prattle" in order to remember "pratar." :)
Is pratar less formal than taler. I some dialect english we would say"he prattles on". Something you might say about someone who is drunk or boring
when is när, but därför att implies a causal relation, and means because.
därför sounds just like therefore! idk it's funny even though i know it's probably bc they come from the same etymology
So, are 'pratar' and 'talar' interchangeable meaning 'speaks' or 'talks,' or are there only certain instances when they're interchangeable?
This was answered above. Basically, "talar" is a bit more formal, "pratar" a bit more casual, but they are pretty much synonymous. Jag talar svenska när jag pratar med henne.