This article is from the Nordic countries FAQ, by Antti Lahelma and Johan Olofsson, with numerous contributions by others.
Danish has three additional letters compared to the English alphabet:
æ, ø, and å (see the section 1.8 on the Nordic graphemes for more
A question often asked by non-Danes is: "Why are Århus and Ålborg
sometimes spelt with double-a and sometimes with a-with-circle? What's
the difference?" Well, it is a matter of old and new spelling
conventions. According to Søren Hornstrup <firstname.lastname@example.org> the
"Nudansk ordbog" (Concurrent Danish) quotes "Retskrivningsordbogen"
for the proper usage of å versus aa:
The letter å was substituted for aa in 1948 as the token for
å-sound. It is still possible to use aa for å in Danish personal
and place names. In personal names you should follow the way the
named person uses. [...]
In Danish place names Å, å is always the correct spelling, e.g.,
Århus, Tåstrup, Grenå. Only if you want to respect strong local
traditions you could use Aa, aa, e.g., Ålborg or Aalborg, Åbenrå or
Aabenraa. In Nordic place names you should use Å, å, e.g., Ålesund,
And from "Håndbog i Nudansk":
It is always correct to use å in Danish place names. But you should
know that you might offend the local residents. [...]
Until 1984 the central administration (statsadministrationen) had
to use å, but in 1984 it was allowed to follow local traditions.
More from the same book:
The Danish alphabet has 29 letters in the following order:
a b c d e f g h i j k l m n o p q r s t u v w x y z æ ø å (aa)
The letter aa is placed in parentheses. This is because it is not
normally used in the language, only in names. Also note that the
capitalization of the double-a is "Aa" and not "AA".
Århus was among the first cities to adopt the a-ring; Ålborg on the
contrary, has been insisting on using the double-a. Since the central
administration between 1948 and 1984 only recognized the å-spelling,
all road signs etc. said "Ålborg". After 1984 when a number of cities
successfully readopted the old spelling with double-a, the new road
signs said "Aalborg". So if you see a sign with the old spelling
(double-a) it is probably a new sign, and if you see a sign with the
new spelling (a-ring) it is probably an old sign ... confused?
Surprisingly perhaps, the reason for cities like Ålborg, Åbenrå, and
Grenå to readopt the double-a is not one of internationalization
(though double-a is surely more "ASCII-friendly" than a-ring) but
rather one of nostalgia, it seems.
The alphabetical sorting is not affected by the aa/å controversy;
Danish person names and place names with aa are alphabetized as if
they were spelt with å (i.e. last in the alphabet), but _only_ when
the aa represents the å sound rather than a "long a". Thus, in a
Danish encyclopedia the city Aabenraa and the author Jeppe Aakjær are
at the end of the encyclopaedia, while the German city Aachen and
Finnish architect Alvar Aalto are found in the beginning!
< A comment from Byrial Ole Jensen: >
This is not quite correct. aa should be alphabetized as å when it is
pronounced as one sound even if it is an "a" sound. So the right place
to search for Aachen in a Danish encyclopaedia is a little after
Åbenrå near the end of the encyclopaedia.
This is according to official rules for the Danish language which is
found in Retskrivningsordbogen (The Dictionary of Correct Writing??).
But I must admit that only few people know this alphabetizing rule and
it is likely that even not dictionaries follow it in order to not
confuse people not knowing the rule. Retskrivningsordbogen itself
places the word "kraal" BOTH between "kr." and "krabask" AND between
"krøsus" and "kråse".