står och [verb], as well as sitter, ligger, etc., are common ways of expressing a continuous action. In other words, they have the same function as "is watching" as opposed to "watches". While you could of course translate them literally in a real-world setting, it makes much more idiomatic sense not to.
springer och is used in a similar construction, but it has a special meaning, or actually two:
Either it means 'to start to do something' (sometimes with a negative nuance)
E.g. springer och skvallrar – literally 'runs off to tell [on someone]' or springer och gömmer sig 'runs and hides' (or 'runs off to hide') (the latter one does not carry any negative value judgement per se)
Or it means 'to do something very often' (probably more often than the speaker would like)
E.g. Han springer på toa hela tiden 'He runs to the toilet all the time' e.g. he goes to the toilet more often than expected. Hon springer och skryter om … 'She runs around and boasts about …' e.g. she keeps boasting about something.
No actual running has to be involved for these sentences to be used!
Since these two already exist, in order to create the continuous form you were imagining, we must add omkring. Then it works: Han springer omkring och tänker på … 'He is running around thinking about …'
Sure, that's what we usually say. Han står och tittar på dig has a stronger continuous meaning than the English continuous in is watching, but with the present, just tittar, there's no continuous meaning.
So when you translate the English continuous into Swedish, you have to either do without that meaning, or exaggerate it. There's no 1=1 match.
Depends on how you define 'idiom'. I'd say it's a grammatical construction. We wrote about them here: https://www.duolingo.com/skill/sv/Continuous-Forms
Could you give me an example sentence in english? I'm trying but only getting really weird ones in my head. This is the best I have so far: "The maid did not like the statue of the late lord of the manor, even though he is stood in a closed room under a sheet." Yeah, it's not great but I've never thought about using (basically past and present) together using passive to make it work. English is odd. Interesting, but odd.
"Yeah, it's not great but I've never thought about using (basically past and present) together using passive to make it work."
Isn't that what you do all the time? You combine a form of "to be" with the past participle of another verb to from a passive construction. "They are seen as a threat." "We are (being) followed."
The difference is that "to stand" normally can't have an object but that doesn't have to apply to the language in northern England. [As far as I know that is a requirement for the assumption to be true. The patient is not to be confused with an object, though, because it's a subject.]
I can't think of any better examples. Maybe: "I'm stood in the hall." - this does pose the problem that that person obviously has not been "placed" in the hall by anyone. I'm still convinced that the sentence has a different meaning than "I'm standing in the hall", in that "I'm stood" has more of a focus on the place you are at as opposed to what you are doing (standing). Interpreting it as a passive construction makes sense to me, but that doesn't have to be correct. I'd definitely say, though, that it is not a substandard form of a simple past or of a past progressive construction.
I can think of only one kind of example of "is stood", and it works only because it's in an idiom that requires an object:
"At the beginning of the play, the main character is stood up by his date, and waits alone in a cafe."
Having said that, I know in parts of the midwestern U.S. it is common to use past participles in ways that sound weird to me — e.g., "the car needs washed" or "the dog needs walked" — so I wouldn't be surprised if there's some dialect that uses "is stood" that way. I have a Gibraltarian friend who uses some construct very much like "is stood" in situations like having to wait for somebody, but I don't remember "stood" being the verb. I'll have to ask her.
I would say it is a regional variation encountered in parts of England. It's not "the Queen's English" by a long shot, but it would be considered correct by those native speakers who use it. Unless you want to pretend to come from a particular region though, it wouldn't be the best form to use.
It's definitely common usage in some parts, the north of England in particular. Equally though, most other English speakers would think it makes you sound uneducated (which is a bit unfair on those who grow up in those parts, but there you go!) More discussion here for the curious: http://forum.wordreference.com/showthread.php?t=694065
I am from the north of England (although my parents aren't and I have spend most of my adult life living in other parts of the UK.) I asked a friend from Berkshire her opinion and she thought if you were talking about where he was, you would say 'he is stood' and if you were talking about what he was doing, you would say 'he is standing', which I thought was interesting.