Frankish vowel shifts
Fragment of a discussion from User talk:Rua
I don't think that's right, either. Germanic *þeutōn would give *thiota in Old Dutch and *diozza in OHG, and the modern words would have been *diet(e) and *Dieß(e). Which is very different from the actually attested words. Dutch tuit can only go back to Germanic *tūt- or *tiuti-/tiutija-.