This is an interesting one. Even today some regional accents are more "hoffähig" - socially acceptable - than others. I would guess that southern german accents were more commonly used at court than in the north.
And ironically that too is of course all about perspective:
While the inhabitants of Northern Germany themselves consider Low German (Platt) boorish and have no equivalent of for example Stuttgart's
Honoratiorenschwäbisch, it was in Scandinavia since the Late Middle Ages / Reformation (together with High German and in Norway also with Danish) a language of authority, power and status:
- religiously (the Danish Bible translation was full of Low German loan words),
- scholarly (university education was only available in Copenhagen (in the Reformation period also Rostock, Greifswald and Wittenberg))
- politically (for the reason given in Reply #8 above) and
- mercantile (because of the Hanseatic League, many South Jutish immigrants in Norway etc.).
Sometimes Low German and Danish clash with regard to phonology, e.g. with regard to p/b t/d k/g lenisation: Low German
hopen, Danish
håbe, Norwegian
håpe, English "hope", German
hoffen. In such cases the Danish form is traditionally given pre-eminence in Norway. (Queen Sonja uses the form
Kongen og jeg håber, the King and I hope.) In many other cases Danish and Low German reinforce each other, e.g. with regard to monophtongisation: Low German
steen, Danish
sten, Norwegian
stein, English "stone", German
Stein. (Again Queen Sonja here uses the monophtonged form, not the Norwegian diphtonged form.) Newer Low German diphtonged forms like
tau, two, thus sound like a contradiction in terms to a Norwegian ear!
And it's more patrician to say
jebursdag as in Berlinish than the pedantic, written form
geburtsdag or the Norwegian calque
fødselsdag!