Where would Joseph Smith have learned to include polysemy in the Book of Mormon?

In Alma 44 we see an example of polysemy (multiple meanings of a word):

And it came to pass that the soldier who stood by, who smote off the scalp of Zerahemnah, took up the scalp from off the ground by the hair, and laid it upon the point of his sword, and stretched it forth unto them, saying unto them with a loud voice:

Even as this scalp has fallen to the earth, which is the scalp of your chief, so shall ye fall to the earth except ye will deliver up your weapons of war and depart with a covenant of peace. (emphasis added)

Matthew L. Bowen notes how both “head” in the anatomical sense and “head”/“chief” in a sociological leadership sense are represented by a single word in Hebrew (rōʾš)1 and Egyptian (tp).

With this in mind, Bowen argues:

…the great fear that the Lamanite soldiers exhibited was due to how they heard the word “chief” used by Moroni’s soldier. If “chief”/“head” (sociological) and “head” (anthropological) were represented by the same term in their own language, they would have not only heard “this is the scalp of your chief,” but “this is the scalp of your head” — i.e., your own “heads.” The scalp, of course, was the extension of Zerahemnah’s anatomical “head,” just as they were extensions of him as their sociological “head” or “chief.” Not wanting their own “heads” to become like their “head”/“chief” Zerahemnah and his fallen scalp, these warriors “threw down their weapons” (i.e., caused them to “fall”) at the feet of Moroni.
– Matthew L. Bowen – The Scalp of Your Head: Polysemy in Alma 44:14–18

Mormon seems to continue this double meaning a few verses later in Alma 44:18:

But behold, their naked skins and their bare heads were exposed to the sharp swords of the Nephites; yea, behold they were pierced and smitten, yea, and did fall exceedingly fast before the swords of the Nephites; and they began to be swept down, even as the soldier of Moroni had prophesied.

Bowen continues:

The “heads” of the Lamanites who refuse the “covenant of peace” become like their head, Zerahemnah and his scalp: “pierced and smitten” (cf. “smote,” vv. 12–13), and they “fall [to the earth] exceedingly fast.” The correspondence between Mormon’s use of the term translated as “heads” here and “chief” (Alma 44:14) becomes clearest when we consider that both are most likely represented by the same word in the underlying text.
– Matthew L. Bowen – The Scalp of Your Head: Polysemy in Alma 44:14–18

Finally, in 3 Nephi 4:28 we see another example of this same polysemy:

And their leader, Zemnarihah, was taken and hanged upon a tree, yea, even upon the top thereof until he was dead. And when they had hanged him until he was dead they did fell the tree to the earth, and did cry with a loud voice, saying:

Why would Joseph Smith add in the extra detail that their “leader” Zemnarihah was hanged at the “top” of the tree? How would Joseph be able to use Hebrew or Egyptian polysemy like this?

See:

Matthew L. Bowen – The Scalp of Your Head: Polysemy in Alma 44:14–18

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