[detaro]

EDIT: following comment is specifically about German German, Swiss German etc do not always work the same

> In German on the other hand, "Ä" is part of the language but not part of the alphabet

Some people claim that, but I wouldn't take that as an authoritative statement. Plenty language authorities disagree, since "ä" and "ae" are not interchangeable.

> it is simply expanded to "AE" as in the previous comment

Only in some contexts (lists of names predominantly), generally "ä" is sorted after "a". E.g. the Duden dictionary goes "zahlen", "zählen", "Zah­len­an­ga­be".