Episode 32: Wednesday

In Old English, the word for Wednesday was Wodnesdaeg, which literally meant ‘Woden's day.’ It comes from a loan translation of the Latin dies mercurii, which literally meant ‘day of Mercury’ (Woden was the Germanic god associated with the Roman god Mercury). This much is for certain. But how did the O in Wodnesdaeg shift to the E in ‘Wednesday?’