There is a significant overlap, but tjej/kille stretches farther up of age, whereas flicka/pojke are reserved mainly for children.
It could be both, since killar och tjejer can also be used about children, but yes, the first translation should be парни и девушки.
Yes, "Guys and Dolls" in the words of stories written in the 1920s almost a century ago, which later became the title of a 1950s Broadway musical, but I can't imagine anyone at all talks like that anymore!
Hmm, I get mixed results when having a stab at new words but usually do better than my guess here 'Killers and traitors'
Teenagers are the most typical killar och tjejer, so yes, sort of. But those words are used very broadly, some people will speak about their newborn kille or tjej, and some old people will think of themselves as kille/tjej too (others may snigger, but still). Also, since they can mean boyfriend/girlfriend, they are sometimes the best word you can think of for your 80 year old neighbor's new sweetheart… so in practice, killar och tjejer can be any age, but the best example of them are teenagers or people in their 20s.
Then it is like in Spanish "chico" and "chica" (boy and girl). It's mainly for young people but you can hear a woman is her 40 or 50 or more talking about her "chico" (boyfriend). At least in Madrid. It sounds a bit weird in Barcelona, though. :) Or a newparent saying his/her newborn is a chico or chica.
Could "killar" and "killarna" refer to a group of mixed genders like "guys" can in English?
Is there a term that would work in such an instance. Guys in English is another way of saying friends and it is likely that a group of friends would consist of men and women.
Not really. If you want to say something like "Hey, guys!", I would probably say something like "Hörni!".
So I guess it wouldn't make sense to append -vän to kille and tjej to make them mean boyfriend/girlfriend in the same way that is done with pojkvän and flickvän?
No, but you can add -kompis to them and create gendered words for people who are just your friends. Hon är inte min flickvän, hon är bara min tjejkompis.
"Compis" is short for "compañeros" in Spanish, and it is used by children mainly. It means friends (at the school). Some adults use it too at work. :) It's like "colleagues".
i am surprised that the k is pronounced /k/, not /ɕ/, what i would have expected because of the following i. why is that?
I noticed that in one sentence that Tjej is translated as girlfriend, Min tjej bor i Sverige, and it will not accept My girl lives in Sweden as correct. However when I use girlfriend here, it then tells me that I am wrong, and will not accept girlfriend as correct, though as mentioned here, it refuses to accept girl.
I am so confused, so this word as different meanings in different sentences, and they are not interchangeable. How do you know what word to use?
kille/tjej can mean either boy/girl or boyfriend/girlfriend. The former is more common but the latter is also perfectly fine - context will normally derive quite clearly which is which. Hence, this sentence is highly unlikely to be interpreted as meaning "boyfriends and girlfriends" unless in very explicit context - and for min tjej bor i Sverige, nobody would ever think you meant anything but "girlfriend".
I think the best literal translation is 'lads and lasses'- in a lot of British folk songs, these terms are used when referring to young men and women (usually in folk songs relating to cheeky ploughboys and busty farmers' daughters...). These terms have changed meaning in common usage since then of course ('lad' often referring to guys who do brash things with alcohol, for example), but the 'old-style' meaning of 'lads and lasses' seems to capture the spirit of 'killar och tjejer' without any infantilising of women!