Historical: Modern readers might presume that the priests of Noah were religious teachers, not scientists.
However, this division of knowledge that is so comfortable to the modern reader, would have been quite foreign to the ancient world.
The priests would have been learned in all aspects of their culture, both religion and their sciences. Thus they were quite able to become teachers of value, even if they elected to leave behind all of their previous religious teachings.
“That They Might Write One to Another”
Historical: It is hard to assess the validity of Mormon's claim that the Lamanites gained writing only through the instruction of the Amulonites.
On the one hand, this is precisely the type of cultural jingoism that one might expect of Mormon. The development of the known writing systems in Mesoamerica precedes this point in time, though the early development and the distribution of writing is not a topic well understood.
While it is yet possible that for this particular group of Lamanites writing was previously unknown, even this possibility is suspicious. When we remember that we are dealing with Nephites-become-Lamanites for the most part, it would be inconceivable that this were the first time writing was introduced to the "Lamanites." Those Nephites who had previously "converted" would surely have taken that knowledge with them, and they should have been in the majority in this particular area.
The most logical explanation for Mormon's assertion is his cultural blinders that asserted that all value came from the Nephites.