Culture: The teaching role of the priests simply recognizes their level of learning. This appointment, therefore, is not necessarily surprising. Why, however, would the Lamanites wish their people to learn the “language of Nephi”? In five hundred years, the two languages would not have moved to complete mutual unintelligibility, except for the proposed cultural milieu in which both groups would be heavily influenced by their absorption into the local population. Even so, that does not explain what is happening here. According to the internal evidence, the “Lamanites” are former “Nephites” who remained behind when Mosiah1 and his people went to Zarahemla. The Zeniffites return to the city of Nephi because Zeniff knows the land and the language. None of the recorded proceedings between Shemlon and Lehi-Nephi indicate any problem in understanding each other. Since the king of the Lamanites referred to here is the king in Shemlon and the priests of Noah were in Lehi-Nephi, then they obviously must have been able to communicate.
The most likely explanation lies in the meaning of “language,” not as the spoken word, but as a synonym for “culture.” (See commentary accompanying 1 Nephi 1:2–3.) If that is Mormon’s meaning here, then the Amulonites are teaching the Lamanites aspects of Nephite culture that would have enhanced their competitive advantage in trading. Verse 7 explicitly links Lamanite wealth to this education and mentions trade (though in a different way than I am suggesting here). However, as suggested in the commentary on verse 1 above, I believe that this is an expression of cultural bias rather than historical accuracy.