Then I noticed something even more specific. Alma-2 (commonly known as Alma the Younger) uses Psalm-language a total of 15 times (according to these two relatively comprehensive sources -- source 1 from John Hilton III and source 2 from Book of Mormon Central). In all but two or three of the examples, the Psalm-language Alma-2 uses matches Psalm-language found on the small plates. This fits very well with another theory I have about Alma-2 having diligently studying the small plates and incorporating their message into his ministry, much more so than other Book of Mormon figures. I'll provide specifics to back up my assertion below.
One caveat before moving on to the specifics -- I personally don't know the Psalms by heart, and so finding additional examples has been difficult for me even with the aid of modern computers. This goes to show how hard it would have been for Joseph Smith to devise this on his own.
Usage of Psalm-language in the first two thirds of the Book of Alma provides us with a very distinct opportunity to test out a theory, because the 21 examples come from just two individuals. Alma-2 is responsible for 15. Ammon gives us 6.
Let's consider Alma-2 and Ammon as individuals. They are contemporaries who were miraculously converted at the same time. Ammon's father was the Nephite King. Alma-2's father was the leader of the Nephite religion. Both were incredible missionaries -- Ammon served among the Lamanites for 14 years, and Alma-2 gave up his position as the chief judge and preached among the Nephites for many years.
Despite all of these similarities, they have one very distinct difference: Alma-2 was a keeper of the records. Ammon was not. Alma-2 had significantly greater access to the small plates than Ammon. My theory is that for this reason, Alma-2 incorporates more of the small plate themes into his literary work than Ammon. He knew the small plates better.
Apparently, this extends to the use of Psalms, too.
Below you'll find two tables. The first table shows the 15 examples of Alma-2's use of Psalm-language. The second table shows Ammon's 6 examples. If the row is colored green, it has a clear match to Psalm-language in the small plate writings. If it is yellow, it has a questionable match. If it is red, it doesn't have a clear match on the small plates.
Table 1. Alma as a Student of the Small Plates
It is also worth noting that similar examples of the Psalm-language in the two red examples can be found in other Old Testament passages, so perhaps Alma-2 is referencing the brass plates or some other lost source rather than the Psalms in those cases. Even so, 12-13 out of the 15 examples fit this pattern very neatly.
Ammon, on the other hand, did not seem to limit his Psalm-language to examples also found on the small plates. In his well-known praise to God in celebration of the astounding missionary success he and his brothers enjoyed among the Lamanites, we find 6 examples of Psalm-language. In Table 2 below, we see that only one of these examples has a clear correlation on the small plates, and there is a plausible explanation for this -- that one instance is also used by Alma-2 twice, once in connection with his conversion story. (In other words, it is possible Ammon is actually quoting something he first heard Alma-2 say in reference to the miraculous conversion event for which Ammon was present.)
Table 2. Ammon as a Control
Conclusion
A few comments:
- It is amazing to me that of all the speakers and writers in the Book of Alma, only three of them use Psalm-language at all. >95% of that is produced by two of them.
- Of those two, we have a clear distinction. 12-13/15 times that Alma-2 uses Psalm-language, he is simultaneously referencing the small plates. Ammon appears to do this once out of six examples, however, the single exception could result from Ammon quoting Alma-2, who in turn is borrowing from Jacob.
- It is really hard for me to believe that Joseph Smith would have been able to keep track of all of this without notes, especially in light of the fact that he dictated the Book of Alma long before he dictated 1 Nephi - Jacob.
- Accomplishing this through naturalistic means without notes would require an exceptional memory and an exquisite knowledge of the Psalms.
- During the dictation of the Book of Alma, Joseph would have needed to remember the "Alma Psalms" (which would later need to be included in the writings of Nephi and Jacob) and the "Ammon Psalms" (which would later need to be excluded from the writings of Nephi and Jacob). All of this information would have to be held in Joseph's mind for at least a few weeks. (In addition to all other internally consistent details.)
- Joseph would also have needed to avoid Psalm-language at all other times while dictating Alma 1-40.
- This is a lot of information to keep track of even for me using a computer. As I stated above, I doubt my own ability to spot additional examples of Psalm-language in the Book of Mormon. Thus, it is reasonable to maintain some degree of caution that additional examples could change these numbers and lead me to a different conclusion.
- Here we have yet another subtle, consistent example of internal consistency. If you believe the Book of Mormon was written by Joseph Smith, you'd have to believe that he went to these great lengths, and then once the book was published, he never mentioned it or pointed it out to anyone.