It probably was a vernacular. Many Hebrew names became shorted. No English equivalent that I know of. Very important Biblical figure.
From Wikipedia:
In Exodus 31:1-6, Bezalel (Hebrew: בְּצַלְאֵל, also transcribed as Betzalel and most accurately as Bəṣalʼēl), is the chief artisan of the Tabernacle.[1] Elsewhere in the Bible the name occurs only in the genealogical lists of the Book of Chronicles, but according to cuneiform inscriptions a variant form of the same, "Ẓil-Bêl," was borne by a king of Gaza who was a contemporary of Hezekiah and Manasseh.
The name "Bezalel" means "in the shadow [protection] of God." Bezalel is described in the genealogical lists as the son of Uri (Exodus 31:1), the son of Hur, of the tribe of Judah (I Chronicles 2:18, 19, 20, 50). He was said to be highly gifted as a workman, showing great skill and originality in engraving precious metals and stones and in wood-carving. He was also a master-workman, having many apprentices under him whom he instructed in the arts (Exodus 35:30-35). According to the narrative in Exodus, he was definitely called and endowed by God to direct the construction of the tent of meeting and its sacred furniture, and also to prepare the priests' garments and the oil and incense required for the service.
Oh Seth, I came across many nicknames written as first name.
I would not hesitate at all and write the full name (Betsalel) in brackets.
My experience is that in Poland and Russia a nickname was placed as first name many times.
the ts sound or c in the name is pronounced like zz in PIZZA.
I am not sure about the German pronunciation of the Z IN ZALLEL.
In transcription, the "tz" sound of Hebrew matches onto a "c" of Polish and a "z" in German. So "Becalel" is the perfect transcription in Polish, and "Zalell" is the correct German transcription of the nickname. In my family, I have a "Salke" spelled in Yiddish with a samech ("s"). He took the English name Charles, like Hatte Blejer also mentions.
Calko Polish and Tsalko (and variants) Lithuanian.
On my Margolis side, he is an ancestor and Calko is on the Margolis side. And maybe somehow he's an ancestor on my Frankel side too, where Tsalko repeats for generations :)
Betzalel ben Chaim, [Maharal's father]