Dear Sandra,

The name Zallel is a shortened form of Betzalel (a Biblical name which is
also written Bezalel; see Exodus 31:1-6). Charles and Carl are English
names associated with Betzalel/Zalel. The connection is assonance.

See http://www.jewishgen.org/infofiles/GivenNames/slide68.html :

"Those named Betzalel often became Charles, because a diminutive of
Betzalel, "Tzali", has a phonetic similarity to a diminutive of Charles,
"Charlie"."

Stephan Parnes
Lancaster, PA