Thanks for the info Spidra..

Warning! Do not answer: "Jo, så äre" if they ask you: "Är du lit dum du ällä?"

Refering to the previous comment about du lit: If people from northern Sweden ask you "Är du lit dum du ällä?" It means: You are a little bit stupid, aren't you? Which would be a normal question if someone tried to use their often used variant of "yes" ssttt.. sttt It sounds like a easy way of getting into the complex social behaviour they got, but it is a false simplicity.

On the matter of Sweden as a core language: This is a tricky question. Swedish, danish and norwegian are all part of (or descendents from) the Norse branch of the Germanic language-tree. However, swedish are strongly coloured by both the high german and low german language during the time between 1100 and 1500. I think this is the reason (even I'm not an expert) the swedish language are more "clear" comparing to danish who speaks (as we see it) "with their porridge still in thier throats". Norwegian have two different languages "bokmål" which is based upon danish. Norway was under danish supremacy from 1397 until 1815 and all their nobles, administration and culture was strongly influenced (if not only) by Denmark/danish. During the time in union with Sweden (1815-1905) the feeling of nationalism grew strong in Norway and when the union was resolved the other norwegian language was "invented", the "nynorsk" (=new norwegian) is a mixture of the different norwegian dialects which is spoked throughout Norway. The latter of the two are more like swedish.

But yes, I would say that as far as I've heard, both norwegians and danish have easier to understand swedish than the other way around. However I know that in Sweden there are hundreds of different local dialects most of them in decline, but the regional dialects are in some places so strong that even inside the country we have barriers when it comes to the spoken word. I myself use to say that I have three different swedish languages, a national, a regional and a local. In my region there is a local dialect who has been so preserved that they say that an englishman and a local man easily can communicate. This because the norse influence on english.
As an example: I assume you know what window means?? ;-) In english = window in älvdalska = windoue or translated to swedish vindöga = wind eye = an eye for the wind. I.e. an opening in a building who let wind, and light into the room. Remember that glass in a window is a very modern phenomena, at least as far north as Sweden.

Well, hopefully I have shed some light upon these matters.

Pozzo