Allen & David Richardson and Anthony Bentley note that just as the Hebrew language uses plural nouns where the English language would call for singular nouns, the Hebrew uses singular nouns where English would prefer the plural. The Book of Mormon demonstrates its authenticity by employing such reversals in number. For example, we see singular-for-plural nouns as: “by the voice of his angels” (Alma 10:20, “by the mouth of his holy prophets” (2 Nephi 9:2), and “with the tongue of angels” (2 Nephi 31:13; 32:2).
Andrew B. Davidson states that: “Words such as hand, head, mouth, tongue and voice are generally used in Hebrew in the singular form when the word is common to a number of persons. In English we would use the plural form.” (Cited in Angela Crowell, “Hebraisms in the Book of Mormon,” p. 5.) [Allen H. Richardson, David E. Richardson, and Anthony E. Bentley, Voice from the Dust-500 Evidences Supporting the Book of Mormon, p. 266]