According to the Comparative Tables, the primitive diphthong [ai] (as well as [ai] from primitive [oi]) first became [ǣ] in the Ossiriandic dialect, instead of being retained as it was in East Danian (PE19/25). A likely examples of this change is Dan. snæ̂s < ᴹ√SNAS in The Etymologies (Ety/SNAS).

See Dan. later [ǣ] became [ē] in Ossiriandic for further discussion.