Oliver Cowdery’s supralinear insertion “in the land” appears to be virtually immediate (there is no change in the quill or the level of ink flow). One could view this insertion as the result of editing since Limhi immediately afterwards asks whether Ammon or anyone he knows can translate these plates—that is, Limhi’s statement that “there is no one that is able to interpret the language or the engravings” (as initially written) is immediately contradicted by his subsequent questions (“canst thou translate … knowest thou of any one that can translate”). However, if Limhi already knows that no one in his own land can translate these records (he presumably tried to find someone), then some kind of postmodification like “in the land” is expected here in Mosiah 8:11. Thus the inserted phrase “in the land” could theoretically be due to editing. On the other hand, the immediacy of the correction in 𝓟 argues that 𝓞 itself read “in the land”.
It should also be noted that in English we actually expect something more like “in this land” rather than the less specific “in the land”. Yet the Book of Mormon text frequently uses “in the land” where modern readers might expect “in this land” or “in that land”, as in these additional examples from the book of Mosiah:
If Oliver Cowdery had decided to edit this passage in Mosiah 8:11, chances are he would have inserted “in this land” rather than “in the land”. Of course, the expected “in this land” and “in that land” do occur in the Book of Mormon, as in the following examples:
But more often, the Book of Mormon text simply reads “in the land”.
Summary: Maintain the phrase “in the land” in Mosiah 8:11, Oliver Cowdery’s virtually immediate correction in the printer’s manuscript and most probably the reading of the original manuscript.