I stream some Swedish crime/mystery TV shows. And more than once I have heard "undrar" in the spoken version being translated as "asking" in the English subtitles. Specifically it went "Varför undrar du? translated as "Why are you asking me?" Can native Swedish speakers please illuminate how "att undra" might be used as a substitute for "att fråga"? Is it a common idiomatic usage?
Yes, it's common and idiomatic. You do say things like I wonder why … in English too, so it shouldn't be too much of a stretch.
Thanks. Using "wonder" in the interrogative in English as in "Why do you wonder?" is much closer in meaning to "Why are you thinking about that?" "Why does it concern you?" We would not use wonder to translate Varför frågar du?" That would almost certainly be "Why do you ask (me)?" or Why are you asking (me) that?" with or without an ojbect pronoun.
Glad to know that it is idiomatic in Swedish. I will listen for it.
Well, that specific translation is very free of course, for one thing we would never accept it in this course. Specifically, adding you is very free. But then again, real life translations and what we are doing here are totally different things.
My spontaneous translation of Varför undrar du? would be more like 'Why do you want to know?' But, Why are you asking? could also work. In a narrative context, you can certainly see things like X undrade varför …Y svarade att … where undrade clearly means that they asked the question aloud. Though you could have written that sentence in English with 'wanted to know' too: 'X wanted to know why … Y answered that …' Which would probably be a closer translation, but not always the most functional one.
Basically, you can't be really sure from the verb undra alone whether the person wondered aloud or just in their head. You have to guess from context.
No but it's possible to say Varför fråga då? to mean 'Why ask, then?'
If you have the present tense form frågar, you need to have some person in the sentence who is doing the asking too. Much like how "Why is asking then?" doesn't make sense in English.
No that would be "Why then ask" I believe, since you aren't putting the då in front of the Varför. I am pretty sure you can say Varfor da fragar (except put in the special characters :p)
You actually can't say "Varför då frågar" – this då is only used at the end of sentences. Also see my answer to pranav_spai.
Another possibility is Varför frågar du då? 'Why are you asking then?'
No, frågar is 'asks' as in 'he asks' but 'to ask' is att fråga.
You're right about frågor – the noun is en fråga 'a question' and the plural is frågor 'questions'.
Would "Why do you question?" be acceptable in this case? In English that would be using question as a verb.
The verb 'question' is ifrågasätter (when it means 'puts into question') or förhör (when it means 'interrogates').
Pronouncing long a, ö, å and Swedish u in a row is quite a challenge, especially when you have none of those vowels in your native language ) Don't think I will ever master Swedish pronunciation, it must be the hardest I've ever encountered.