Use the more refined repo by Pascal Landau at https://github.com/paslandau/german-stemmer .

GermanStemmer

Takes a word and reduces it to its German stem using the Porter stemmer algorithm.

References:

- http://snowball.tartarus.org/algorithms/porter/stemmer.html
- http://snowball.tartarus.org/algorithms/german/stemmer.html

Usage: $stem = GermanStemmer::stem($word);

NOTE: You must open this document as a UTF-8 file, or you'll override the accented forms.