Where does the name Letty come from?

The feminine given name of Letty is usually a shortened (pet) form for Elizabeth; meaning God's oath, consecrated to God. Variations include Elissa, Yelizaveta, Elizabeth, Elisheva, Lisette, Elsa, Leta, Letitia, Lisa, Lizette, Lizzie, Lise, Libby, and Lettice.