Ross Geddes (personal communication, 12 September 2004) suggests that there may be some defect in the text with respect to the specification “on the west sea south”. He first notes that the text literally states the Lamanites were “on the west sea south”, yet elsewhere the text uses only prepositions that are literally appropriate for being on the seacoast:
In other words, with sea we can have prepositions like to, by, unto, near, and nearer, but there are no examples that use on except in the earliest extant text for Alma 53:8. Of course, we cannot say that on is impossible here since such usage does occur in English (as in “he has a cabin on Lake Ladoga”).
Referring to examples like Alma 52:12 (“on the borders by the west sea”), Geddes suggests that Alma 53:8 could be emended to read “the armies of the Lamanites on the borders by the west sea south”. Such an emendation would assume that during the dictation of the text, the borders by was accidentally omitted, a reasonable enough possibility. Nonetheless, we should note here that Alma 53:8 also has an unusual noun phrase, “on the west sea south”, not the more expansive expression “on the south by the west sea” (the reading in Alma 53:22). This means that Alma 53:8 has two unique characteristics: (1) the nonliteral use of the preposition on to refer to the location of the Lamanite armies and (2) the succinct noun phrase west sea south. It seems doubtful that we would want to emend this noun phrase as well. In other words, the phraseology in Alma 53:8 is unique in more than one way, which suggests that it would be best to leave the whole original reading unchanged. Not only is it understandable, it is also fully extant in 𝓞.
Summary: Maintain in Alma 53:8 the original reading “the armies of the Lamanites on the west sea south … had gained some ground over the Nephites”; this clause, unique in more than one way, is fully extant in 𝓞 and is understandable.