"I listen to the story."
Translation:Éistim leis an scéal.
So just to make sure I understand... I get Eistim, because I'm the one listening... is it "leis" because it's referring to "an sceal"? Meaning why leis instead of liom? I have in my notes that "eist (le)" means "listen (to)", but I didn't realize the "le" part needed to be conjugated as well, and I'm not sure what it's based on for this sentence.
In this sentence, "leis" does not mean "to him;" rather, here, "leis" means "to" (and yes, "le" or "leis" can mean "with," but in English, of course we say "listen to" rather than "listen with," so I'm going to use "to" rather than "with" throughout this answer). The point is, yes, "le" + "sé" = "with him" / "to him" but here "le" simply becomes "leis" before "an:" "leis" is simply the form that "le" takes when followed by "an," as you observed. (As in English, "an" is the form "a" takes when followed by a vowel: it's just a different form of the same word).
This "leis" has nothing to do with the gender of the object:
Éistim leis an scéal. = I listen to the story ("scéal" is masculine).
Éistim leis an nuacht. = I listen to the news. ("nuacht" is feminine).
And yes, you can say "éistim léi" but that would mean "I listen to her:"
Éistim leis an bhean. = I listen to the woman.
Éistim léi. = I listen to her.
Éistim leis an bhfear. = I listen to the man. (here, "leis" is "to" / "with"). Éistim leis. = I listen to him. (here, "leis" is "to him" / "with him").
So, gender does matter if you are using "le + pronoun:"
Éistim leis an scéal; éistim leis. = I listen to the story; I listen to it. Éistim leis an nuacht; éistim léi. = I listen to the news; I listen to it.
Edit: Changed "Éistim leis an fear" to "Éistim leis an bhfear."
No, you don't add a fada when it's feminine. The 3rd person singular feminine prepositional pronoun for le is léi (liom, leat, leis, léi, linn, libh, leo).
For ag, the 3rd person singular feminine prepositional pronoun is aici. For ar, it's uirthi, for roimh, it's roimpi. They all use the letter i, without a fada.
No, a prepositional pronoun is a compound of a preposition and a pronoun.
The preposition changes depending on particular meaning you need to convey. If the object of the preposition is a pronoun, they are combined, so the preposition ag has 7 prepositional pronouns associated with it, but if the object isn't a pronoun, you just use ag.
It's misleading to say that "the prepositional pronoun changes", because that suggests that there is one modifiable prepositional pronoun, but there are lots of different prepositional pronouns, 7 for each preposition (though in the case of idir, some of them are more theoretical than practical).
It wouldn't be a valid translation because that's not how Irish speakers say "I listen to the story".
Why do you "look at" but "listen to"? The preposition used is simply a convention, it doesn't actually mean anything, and Irish doesn't use the same conventions that English does.