For a while I have wondered why the root for the copula (in English the verb "to be" but not used in the same way in all other languages) is different in Arabic and Hebrew.
In Hebrew the root is ה.י.ה (H-Y-H), in Arabic it’s ك.و.ن (K-W-N).
Similar (to the Hebrew root) words in Hebrew include words like הוא = /hu/ = "he" and היא = /hi/ = "she" and other words that describe identity. Those same words exist in Arabic too (although there they are spelt without the final Alef) and I think they derive from a common root ה.י.ה that survived in Hebrew to mean “to be”.
In Aramaic the root is ה.ו.י (H-W-Y). I am sure that root is related to the Hebrew root. (Find an Aramaic root dictionary here.)
He, Yud and Waw have a tendency to replace each other depending on a word stem. He can become Yud[1], Yud can become Waw[2]. So the roots ה.י.ה and ה.י.י are pretty much the same root.
Similar (to the Arabic root) words in Hebrew include להכין (lehakin) which is a Hif3il verb meaning “to prepare”. Assuming it derives from the root K-W-N for “to be” the Hif3il verb literally means “to make to be” which does fit a meaning “to prepare”. Other Hebrew words derived from the same root include מכון (makon = “institute”, literally “prepared place” or “place of being”), נכון (nakon = “correct”) and perhaps כן (ken = “yes” or “so”).
It doesn’t help that the word “to be” (in the sense of “to exist”) in Akkadian (East-Semitic) is “bašu” (the “š” is a Shin), probably related to Akkadian “bišitu” (“property”).
And in Amharic (Ethiopian) it’s another root still.
This is clearly too much for now.
Updated 18 February 2016. Tel Aviv.