Yes, idiomatic. Things ar not always completely literal. Think how many idiomatic expressions there ar in English. Meanwhile, in Welsh there is tŷ bach, literally 'small house' but taken to mean 'toilet'. And, perhaps mor nearly parallel to this Irish example; in Chinese, zǒu literally means 'to walk' but can be taken to mean 'to go' or 'to leav'. Chinese also has pá shān, literally meaning 'mountain climbing' but is taken to mean 'hiking'.
Yes. In modern German, "gehen" means both go and walk, with the past participle "gegangen" and noun "gang," which survives in English in "gangway." If something is "im gang," it's in progress, and of course "Wie geht's" translates as "How are you" but is literally "How goes it?"
This makes me feel a little confused. Could you please clarify what direct and indirect relative clause are? Sorry, I usually don't have problems with grammar, but I'm not a native English-speaker so I may be unfamiliar with the terminology, and the lack of examples doesn't help me much...
Funny how native English speakers have hard time with the idiomatic meaning of 'to go' here - to me this is very similar to the "going on" in English? It could literally mean walking, but it has been grammar-ified into "sth is happening". Of all the weird idioms, this one is actually quite transparent to me (German)
Just as a side note - I find it interesting that the metaphor of going/walking plus a preposition is common for an unknown activity in several languages - English, Irish, German ("Was geht da vor" literally "what is going ahead there") French? ("Qu'est-ce qui se passe" my French is not a lot better than my Irish currently, but it looks to me there is "passer" = "pass, go by" in there somehow)... Maybe a generalization from "who goes there" ?
So my question would be is this how people today actually say "What is going on?" in Irish. I mean is is used a lot? Or is there another way of saying "What is going on?" that is used more because "What is afoot?" isn't exactly used in English anymore and I wondered if it was the same for Irish.
Yes, Cad/Céard atá ar siúl? is exactly how people say "what's happening?" or "what's going on?" today. It's not the only way to say that, but it is a common and current usage.
The only connection with "afoot" is that you use your feet to siúl, indicating that, even in English, the concept of using the word siúl for this idiom isn't all that strange.
So essentially you are saying that, from an Irish perspective, English using the word "playing" for this is weird?
Off-topic anecdotal note; in my native language (Dutch) we also use that word for films. In fact, the word for a full length film is "speelfilm" which literally translates to "playing-film".
"What goes on" uses the habitual present, "what is going on" uses the progressive present. In both English and Irish these are two different things, and they are not generally interchangeable.
"I wonder what goes on in there?" suggests that there are things happening "in there" on a regular basis, "I wonder what is going on in there" refers to the current activity happening "in there".
I had noticed that this expression appears to have a literal meaning very close to the now admittedly fairly uncommon though perfectly correct English expression "What is afoot?", which means "What is going on"? Both the Irish and English use a similar metaphor. Unsurprisingly, the program didn't know it.
siúl is not the Irish for "foot", so it's a bit of a stretch to suggest that ar siúl is "very close" to "afoot", but, as has been pointed out already a number of times, you do use your feet for walking.
But the reason that Duolingo doesn't (and shouldn't) accept "what's afoot?" as a translation is that just isn't a common idiom in English any more, and the purpose of Duolingo isn't simply to test your comprehension of Irish, it's also to teach you how to translate things that you do say in English into Irish, and people do say "What's going on?". ar siúl is also used to say things like An obair atá ar ar siúl - "the work in progress"/"the work that is going on", and Tá tú ar siúl arís! - "You're at it again!*, which don't really tie in well with "afoot".
"it's a bit of a stretch to suggest that ar siúl is "very close" to "afoot""
That's not true though, "to be afoot" literally does mean "to walk". In Dutch also, a pedestrian is "te voet" (which translates to both "afoot" and "walking").
But I do agree with the rest and that this isn't something people actually say.
The Irish for "foot" is cos, not siúl. There is absolutely no etymological connection between the two - they are not "close" in any way, and Winchelsea specifically referred to "a literal meaning very close to"
Winchelsea then went on to repeat something that had already been pointed out and discussed in some detail in the earlier comments that they apparently hadn't taken the time to read. Obviously, you use your feet to walk but that doesn't make ar siúl very close to cos.
IN this case, ar indicates a state - ar siúl meaning in a state of motion, or "going on".
ar diol is another example ("in a state of sale") but it is usually translated as "for sale", rather than "selling", to differentiate between something that a seller does, and the state of the thing that's being sold.
cad and céard are basically dialect variations - goidé also crops up in Ulster Irish in place of cad é or céard é.
cén can often be better thought of as "which", and you can't swap cad for cén - you can often ask a question using either cad or cén, but you have to make significant changes to the sentence for that to work.