Jacob tells us much more about Sherem, all of which fits into the model suggested. Sherem is well educated. In a world where there were no universities to carry weight by association, Sherem had to demonstrate his learning in public discourse. He was clearly able to do so.
The comment about Sherem's "perfect knowledge of the language of the people," can be read in two ways. The first, that his education allowed him to be verbally artistic with the language. The second, however, would suggest that not only was this first meaning applicable, but that this was not his native language! Were Sherem fluently speaking in a second tongue, it would be patent demonstration of his great learning, probably a learning beyond that of any known to the Nephites, including the traders. The traders wold certainly know how to communicate in the language of the people with whom they traded, but communication and fluency, and artistry above that, are quite different things. One who is able to be artistic and influential in a foreign language impressively demonstrates his learning.
Jacob terms this use of language flattery, but also recognizes it as "power of speech." Sherem is impressive not only in what he says, but apparently in personal prestige. He appears to be educated above the Nephites to whom he speaks. He presents a degree of education and learning to which they might aspire, and which they certainly respect. Again, this all points to a foreigner.