The text from which the Book of Mormon was translated was engraved on plates in a language Mormon refers to as “reformed Egyptian” (Mormon 9:32), a more succinct and space-saving form of expression than the native Hebrew.
The language of the Book of Mormon evolved as a blend of Egyptian (well known in the Palestine of Lehi’s day) and Hebrew—much the same as modern English is a blend of multiple languages (see Nibley, 13–14). As Mormon explains, because “none other people knoweth our language, therefore he [the Lord] hath prepared means for the interpretation thereof” (Mormon 9:34). Thus Nephi’s statement that the record he makes consists of both “the learning of the Jews and the language of the Egyptians” (1 Nephi 1:2) makes eminent sense, culturally.