The Stuttgart-Tubingen Tag Set (STTS) (Schiller et al., 1995) has long been established as a quasi-standard for part-of-speech (POS) tagging of German. It has been used, with minor modifications, for the annotation of three German newspaper treebanks, the NEGRA treebank (Skut et al., 1997), the TiGer treebank (Brants et al., 2002) and the TuBa-D/Z (Telljohann et al., 2004). One major drawback, however, is the lack of tags for the analysis of language phenomena from domains other than the newspaper domain. A case in point is spoken language, which displays a wide range of phenomena which do not (or only very rarely) occur in newspaper text.