The colon here is similar to how we sometimes use the apostrophe to make plurals of acronyms in English, only here we're making the definite form. TV's, CD's DVD's; tv:n, cd:n, dvd:n.
(Some comments below point out that even though the apostrophe is commonly used to pluralize acronyms, it is more acceptable to simply add an 's' unless this creates any sort of ambiguity.)
Agreed. Here is some advice from the Grammar Monster (http://www.grammar-monster.com/lessons/apostrophes_show_plural_of_abbreviations.htm)
AVOID USING AN APOSTROPHE
Some grammar pedants claim that apostrophes cannot be used in any plurals. This is an outdated, dogmatic view. If you have an awkward abbreviation, number, or letter and using an apostrophe to show its plural assists your readers, then go for it.
APOSTROPHES IN PLURALS FOR UPPERCASE ABBREVIATIONS
When writing titles, you are sometimes compelled to use just capital letters. This makes it difficult to show a plural of an otherwise normal-looking abbreviation. Remember, if it assists your reader, you can use an apostrophe to show a plural. For example: CD'S ARE OBSOLETE
TWO LRS'S PER PROCESSOR
I don't agree with Grammar Monster on this. The apostrophe is not logical in creating plurals. It definitely indicates possession, and using it for plurals increases confusion rather than making things more clear. There is no need for an apostrophe. Also, why is the "s" capitalized? I'm not impressed with Grammar Monster based on this quote. I do agree that the "apostrophe s" is accepted, but a good editor would fix that before publication.
To those of you who didn't get AxeKitty's joke, see this: https://www.duolingo.com/comment/6191706$comment_id=10994126
It is not incorrect in English. It once was, but it has become so ubiquitous as to be accepted by most style guides. Find me one that says otherwise, and I'll find you three that support this statement. Here's one: http://www.public.wsu.edu/~brians/errors/acronyms.html
Yeah! Here's a sentence from Finnish Wikipedia: "Väestötiheys EU:ssa on 115,6 asukasta/km²" ("The population density in the EU is 115.6 inhabitants per km²"). The inessive case ending "-ssa" is separated from "EU" by a colon. Whereas "kala" ("fish") is written "kalassa" in the inessive case :)
It probably helps in the pronunciation, imo. "Teven" would be pronounced as two syllables (/te -ven/), whereas TV:n makes the speaker almost separate the /e/ of the ve from the /e/ of the :n. That is, /te - ve - en/. What do you say, Helen? You're the Queen of Forvo... =D
Ha ha, I guess the TV:n writing is a bit misleading for a non-Swede. It is pronounced exactly like teven :). If you prefer to write it out, it works fine for this acronym but not for all. You mustn't write veden instead of VD:n (the CEO) for example. It's the definite of "ved", which means firewood, and here the pronunciation of VD:n, the CEO, and veden, the firewood, differs.
Looks at the bottom of this section on Wikipedia for more examples of this:
I would never say "TV" in English. I know millions do, but in some circles (clearly my own) it is considered a poor substitute for "telly". I'm now amusingly forced to say it in Swedish!
So this 'helt' means the subject is completly new, as in brand new. If I had a plural subject and I wanted to use it as an adverbe, so "the apples are all green" (100% green in colour) as opposed to "the apples are all green" (100% of the apples are green) Can I make this distinction in Swedish?
Only rarely. As in English, we can use it to show a contraction, e.g. sta'n for staden which later turned into just stan. It's also used when there's risk of confusion, for instance to show possession after a name ending in s, such as Tomas/Tomas'. Again, though, these are both very rarely used.
It's a set phrase, "brand new."
"Brand" by itself never means "completely."
"Brand new" means something like "very fresh," "just made." You can say, "I have new shoes (maybe bought them a week ago)," or "I have brand new shoes (probably wearing them for the first time today)."
Apparently, the phrase "brand new" harks back to times when a brand was put on a piece of merchandise (a horse shoe, etc.) as the last thing before placing it up for sale. The idea is that the thing has not been used much or at all yet.
The Swedish phrase seems to mean more like "100% new," and the English phrase means more like "freshly made," which is a slightly different way of saying it, but the meaning is the same: The t.v. very recently came out of the box.
Put simply, it's because the adjective comes after the noun. I've written a little more about it e.g. here: https://forum.duolingo.com/comment/26420394/Answers-to-some-common-questions-on-grammar-that-beginners-have