>No, AFAIK all German dialects, plus Dutch, have *þ- -> d-; *þ- ->
>t- is North Germanic (plus Frisian?).
In (all) German (dialects) P, T, K / B, D, G are interchangeable,
i.e. no strict rules. Hence teutsch/deutsch, Tal/Dahl, Berger/Perger,
Bayr/Payr & the like; hence the Austrian-South-German spelling -egg-
for -eck- (Schwarzenegger as variety for Schwarzenecker); hence the
pronunciation [flakke] for Flagge by most Germans.
(Also damit kannste wirklich nix anfangen - zumindest auf Deutsch.)
George