Dan. [a] became [e] after initial [s] + voiceless stop; [s{ptk}ă-] > [s{ptk}e-]

Dan. [a] became [e] after initial [s] + voiceless stop; [s{ptk}ă-] > [s{ptk}e-]
In some circumstances, primitive short [ă] became [e] in Danian. The two clear examples of this are sc(i)ella < ᴹ√SKAL¹ and spenna < ᴹ√SPAN (Ety/SKAL¹, SPAN). There are also quite a few cases where primitive short [ă] was preserved, such as alm, hrassa and swarn. I don’t know of any similar change in the real-world Germanic languages, so my best guess is that the change [ă] > [e] occurred after an initial cluster of [s] plus a voiceless stop (p, t, k), but this is purely speculative.

Phonetic Rule Elements

[skă-] > [ske-]
[spă-] > [spe-]

Phonetic Rule Examples

skallā > skellā skă- > ske- ᴹ√SKAL¹ > Dan. sc(i)ella ✧ Ety/SKAL¹
spannā > spennā spă- > spe- ᴹ√SPAN > Dan. spenna ✧ Ety/SPAN