Perhaps Ammon provided some response indicating that Ammon himself could not translate. Therefore, the question becomes whether Ammon knew of anyone who could. The answer is important. Not only does Ammon answer that the Nephite king could translate, but he does so without knowing anything about the language encoded in the engravings. The question might have been implicitly about this particular set of plates, but the answer included any ancient language encoded as a script.
The means by which the Nephite king could translate is that he possessed “wherewith that he can look, and translate all records that are of ancient date, and it is a gift from God.” The first question we should ask is how Ammon would know that. The answer is Mosiah (Benjamin’s father) had already used those interpreters to read a large stone the people of Zarahemla brought to him not long after the Nephites arrived in Zarahemla (see Omni 1:20–22). Although it isn’t discussed at this point, it is important to note that Mosiah’s translation of the stone also told of a people who had been destroyed and whose bones lay in the lands northward. Although that information comes from Omni’s record, which Mormon did not use as he wrote his book, it is probably an event that Mormon would have told precisely because it spoke of a destroyed people in the lands northward.
One who used interpreters was called a seer, clearly because the user saw something when they were being used. It was a term with which the Book of Mormon’s 19th Century audience was familiar. The question many have asked about the interpreters that Mosiah used is: ”Where did they come from?” The question is typically asked because there is an assumption that there was only a single set of interpreters. There is no reason to make that assumption. Mesoamerican shamans, even to this day, use items, sometimes stones, as a means of seeing what otherwise could not be seen. The importance that will be emphasized concerns the seer, not the specific mechanism the seer uses. Joseph Smith used various seer stones in addition to the interpreters that were buried with the plates. There is no need to suppose any reason that the ancient Nephites could not have had their own stones without waiting upon Jaredite stones.