ppl say teedus because that is the pronunciation of it in japanese, but there is tiedus also which is the american pronunciation for it. you can say it either way. it doesn't matter.
Kawaii, how can that be the official one if thousand or possibly even millions of ppl say tiedus? u have no basis for teedus being the american pronunciation while i do since our pronunciation follows many rules that change the sound of a letter for a particular reason.