Page "Diacritic" Paragraph 104

Languages that treat accented letters as variants of the underlying letter usually alphabetize words with such symbols immediately after similar unmarked words.

For instance, in German where two words differ only by an umlaut, the word without it is sorted first in German dictionaries ( e. g. schon and then schön, or fallen and then fällen ).

However, when names are concerned ( e. g. in phone books or in author catalogues in libraries ), umlauts are often treated as combinations of the vowel with a suffixed e ; Austrian phone books now treat characters with umlauts as separate letters ( immediately following the underlying vowel ).