Non-LDS scholar, Lester L. Grabbe, in a rather poorly-argued chapter, to be perfectly frank, comparing and contrasting Joseph Smith with Old Testament prophetic figures, did offer the following on the visit between Charles Anthon and Martin Harris which is of note:
To be fair, he does wonder on p. 116 about Harris' statement that "Anthon affirmed the characters were 'Egyptian, Chaldeak, Assyriac, and Arabic' . . . [while] knowledge of the decipherment of the Egyptian . . . did not reach England until 1838 nor the United States until sometime later, while decipherment of Akkadian cuneiform did not come along until some time after this." However, Harris' comments about his meeting with Charles Anthon contain too many elements that reflect an origin from a trained linguist than something he came up with to justify his acceptance of the Book of Mormon and Joseph Smith's prophetic claims. See the paper, "What Did Charles Anthon Really Say?" by Robert D. Smith, Gordon C. Thomasson, and John W. Welch here. Further, on this topic, Grabbe is in error; nowhere is Akkadian mentioned in Harris' report; further, in Joseph Smith's time, "Chaldeak" = Aramaic and "Assyriac" = Syriac).
I think we have to accept that Anthon's two accounts were self-serving. One suspects that if the entire truth were known, there might be some embarrassing aspects for him and his professional reputation. It would not surprise me if Anthon was taken in temporarily by the lines on the paper, or at least was open to their authenticity, until Harris enlightened him as to their origin. So his claim to have immediately recognized it as a hoax rings hollow . . . regardless of what precisely passed between Anthon and Harris, it seems without doubt that the latter returned from the trip convinced of the authenticity of the plates and their writing (Lester L. Grabbe, "Joseph Smith and the Gestalt of the Israelite Prophet in Ancient Israel" in The Old Testament in its Social Context, ed. Philip F. Esler [Minneapolis, Minn.: Augsburg Fortress Press, 2006], 111-128, here, pp. 115-16)
To be fair, he does wonder on p. 116 about Harris' statement that "Anthon affirmed the characters were 'Egyptian, Chaldeak, Assyriac, and Arabic' . . . [while] knowledge of the decipherment of the Egyptian . . . did not reach England until 1838 nor the United States until sometime later, while decipherment of Akkadian cuneiform did not come along until some time after this." However, Harris' comments about his meeting with Charles Anthon contain too many elements that reflect an origin from a trained linguist than something he came up with to justify his acceptance of the Book of Mormon and Joseph Smith's prophetic claims. See the paper, "What Did Charles Anthon Really Say?" by Robert D. Smith, Gordon C. Thomasson, and John W. Welch here. Further, on this topic, Grabbe is in error; nowhere is Akkadian mentioned in Harris' report; further, in Joseph Smith's time, "Chaldeak" = Aramaic and "Assyriac" = Syriac).
