Dixdeaf! Is this another one of those made up titles? =p
If you wanna be anal about it, like Quibus correcting everyone that writes Usas instead of Uşas, then don't write Dixdeaf or Dixdaef. Write it as D' [diːdæʃ]. D' is the title, and the latter part is a linguistic thing, explaining how to pronounce D': [diːdæʃ] --> "dee dash". Maybe Tecno Soft thought it was cool to add it, I think it's silly.