"What are you doing this weekend?"
Translation:Vad gör du till helgen?
I wonder why would it be "i helgen" but not "i helg", since in the english sentence the word "weekend" is not in definite form?
It’s just that Swedish uses the definite form here while English doesn’t. Sometimes there is not a 1:1 overlap.
but why is it definite while the other examples are indefinite? like i dag, i natt, i kväll
In Swedish, abstract nouns and days (måndag [Monday], tisdag [Tuesday], sjukdom [illness], etc) often take the definite declension in a sentence, whereas in English we would normally not use a definite article.
For example: "På fredagarna går vi till Finland" translates to "On Friday's we go to Finland."
"Vi går till Norge i kväll" translates to "We are going to Norway tonight."
It simply comes down to memorizing where certain articles (definite or indefinite) are and are not used in Swedish versus English. Hope this helps!
Although, literally that would be "Vad ska du göra i helgen" and has a slightly different nuance to it:
"Vad [gör] du | What [are] you doing" sounds like a bit more definite plans of action than;
"Vad [ska] du göra | What are you [going to] do", which (to me at least) is closer to planning on maybe doing something, but will it actually get done remains to be seen.
That's how I've understood the latter. Please do correct me, people, if I've got it wrong (in any language, or in the meaning of it).
According to my notes, you can use på for generalizations (days of week, times of day, and seasons) and also a future specific day of the week. Maybe other time-related things, but this is all I've learned so far :)
For example: på onsdag = on Wednesday (upcoming), på onsdagar = on Wednesdays (generally), på morgonen = in the morning (generally).
Don't try to figure out the logic, I think there is none; you simply need to memorize each case.
Generally speaking, till is "to" and tills is "until". But there's overlap, colloquial usage, and idiomatics coming into play as well. In this case, till helgen and similar phrases (e.g. till sommaren) is a fixed phrasing for "over the weekend".