Re: Keile/Kayla/etc - Yiddish?
The main difference in the German (non-Jewish) pronunciation of Abigail is the letter b, the last two syllables may be contracted into one, giving /a-bee-giel/ as the result. Germanic Geila comes from a completely different root (by searching the submitted names for geil* you can find a few rare names with that root) and I don't think it is relevant here. It was never big in Old High German and later acquired the new meaning "horny" leading to the death of names containing that name element.