“Yea, I make a record in the language of my father, which consists of the learning of the Jews and the language of the Egyptians” 1 Nephi 1:2
Despite rampant “Egypt-o-mania” in the early nineteenth century, the notion of Jews writing in Egyptian was an unimaginable concept, and Joseph Smith was roundly criticized on this point by early Book of Mormon critics. In this respect, the Book of Mormon has aged better than its detractors.
More at https://knowhy.bookofmormoncentral.org/content/did-ancient-israelites-write-egyptian