Dan. sc(i)ella n. “shade, screen”
A noun glossed “shade, screen” developed from the root ᴹ√SKAL¹ (Ety/SKAL¹), perhaps from a primitive form *✶skallā (though Helge Fauskanger suggested ᴹ✶skalnā). As noted by Helge Fauskanger (AL-Nandorin/scella), it seems the vowel [a] became [e]: scella. The mechanism is unclear, but perhaps this change was triggered by the initial [s] plus voiceless stop. Also noted by Helge Fauskanger, the word seems to have undergone further vowel-breaking of [e] to [ie]: sciella. The mechanism here is easier to explain, probably analogous to similar changes in Old English, where [e] became [ie] after initial [sk].
References ✧ Ety/SKAL¹; EtyAC/SKAL¹
|ᴹ√SKAL¹ > sc(i)ella||[skallā] > [skellā] > [skellā] > [skella] > [skiella]||✧ Ety/SKAL¹|