Our understanding of Joseph Smith’s education is estimated to put him at a third-grade education in modern Western schools, but a third grade education does not match the type of language used in the Book of Mormon.
In 2019, Brian C. Hales submitted the text of the 1830 Book of Mormon to the most widely used computerized text readability and complexity tests which resulted in scores of reading grades up to eleventh grade, and scored as “Fairly difficult to difficult to read”. From this analysis, it is clear that the Book of Mormon is written at a higher grade than Joseph was educated.
Separately, BYU Professor Roger Terry identified words found in the Book of Mormon which we would not expect from a third-grade education:
Why would these words have come to Joseph as he dictated the text? How did he manage to compose a book with such a high reading age if he was “merely instructed in reading, writing and the ground rules of arithmetic”?