Reference: Verse 11 is a verbatim quotation of Isaiah 11:5, and verse 12 quotes Isaiah 11:6 with only a slight change. The KJV Isaiah reads: “And then shall the wolf also shall dwell with the lamb, and the leopard shall lie down with the kid; and the calf and the young lion and the fatling together; and a little child shall lead them.” The slight change is the introductory addition of “and then shall” (v. 12) with a required minor shift in word order. This addition is not a variant but a syntactical smoothing to allow Nephi to integrate Isaiah into his own text.
Nephi is not using Isaiah as a sacred text whose wording is immutable, but rather as a dynamic and integrated part of his message. The historical text comes alive in Nephi, lending itself readily to the same verb tenses and meanings as the rest of Nephi’s discourse. This is a change that comes from Nephi’s use of the text, not from any putative translation of Isaiah.
Vocabulary: The “girdle” in verse 11 is a belt. Isaiah is using parallelism to indicate how the righteous will be “clothed.” The belt is around the “loins” and “reins.” Both of those terms indicate the waist, hence Blenkinsopp translates this verse: “Justice will be the belt around his waist, truth will be the band around his middle.”