[E. C. Briggs report to Joseph Smith III of interview with David Whitmer]
... [Emma] remarked of her husband Joseph's limited education while he was translating the Book of Mormon, and she was scribe at the time, "He could not pronounce the word Sariah." And one time while translating, where it speaks of the walls of Jerusalem, he stopped and said, "Emma, did Jerusalem have walls surrounding it." When I informed him it had, he replied, "O, I thought I was deceived."
... "In June, 1829, I [David Whitmer] saw the angel by the power of God, Joseph, Oliver and I were alone, and a light from heaven shone round us, and solemnity pervaded our minds. The angel appeared in the light, as near as that young man. [Within five or six feet]. Between us and the angel there appeared a table, and there lay upon it the sword of Laban, the Ball of Directors, the Record, and Interpreters. The angel took the Record, and turned the leaves, and showed it to us by the power of God. They were taken away by the angel to a cave, which we saw by the power of God while we were yet in the Spirit. ...
"The boys, Joseph and Oliver, worked hard, early and late, while translating the plates. It was slow work, and they could write only a few pages a day."
Of Joseph he continued;
"He could not do a thing except he was humble, and just right before the Lord."
I said, "Why not?"
"The Urim and Thummim would look dark; he could not see a thing in them."
"How did it appear in them?" we asked.
His answer was:
"The letters appeared on them in light, and would not go off until they were written correctly by Oliver. When Joseph could not pronounce the words he spelled them out letter by letter. ...
[E. C. Briggs to Joseph Smith III, 4 June 1884, Saints' Herald 31 (21 June 1884): 396-97., as cited in Dan Vogel, Early Mormon Documents: David Whitmer Interview With E. C. Briggs And R. Etzenhouser]