In 1997 he earned his habilitation with a second thesis, Dialektdynamik in Mittelitalien: Sprachveränderungsprozesse im umbrischen Apenninenraum ("Dialectal dynamics in central Italy: Language evolution in the Umbrian Apennines").
He is a Wikipedia author who served as a member of Wikimedia Germany's advisory board (2005–2007); he did not stand for re-election.
[1] Living mainly in Berlin, he is a member of the Chaos Computer Club, having served since 2009 as its board representative to the experience exchange groups (Erfahrungsaustauschkreise).
Haase is a polyglot; he speaks German, English, French, Italian, Spanish, Basque and Esperanto, as well as the Catalan and Occitan.
He is also able to read Latin, Ancient Greek, Sanskrit, Gothic, Dutch, Romanian, Russian, Maltese, Swahili and Samoan, and to communicate using German Sign Language (Deutsche Gebärdensprache, DGS).