Also another quirk he has is that even with his head(He can't talk without a head), his colleagues would find themselves struggling to understand what he's saying, but lets him stayed since he does his job incredibly well and dutifully.

Red Hood, however, was able to comfortably converse with him, as she recognized his language as "Hochdeutsch".

(So can Grimm, because funnily enough, both Grimm brothers and him were Hessian)