In this example, Oliver Cowdery correctly copied the original manuscript’s Brethren into the printer’s manuscript, but then later (with a sharper quill and a heavier and darker ink flow) he overwrote the e with an o and the final n with an s. He undoubtedly intended the resulting Brothres to represent the word brothers. The 1830 compositor set it as such and subsequent editions have retained brothers.
The plural brethren is much more frequent in the Book of Mormon than brothers (549 to 9 in the earliest text). Semantically, both brothers and brethren are used to refer to blood brothers:
In fact, brothers is used only with respect to blood brothers, but the singular brother can also be used to refer to a brother in the faith, as at the beginning of Helaman’s epistle to Moroni in Alma 56:2 (“my dearly beloved brother Moroni”).
In 1 Nephi we have several examples of the scribes mixing up brethren and brothers, as well as the singular brother with the plural brothers. Much of the first mix-up has to do with the pronunciation of the word brethren. Besides the instance here in 1 Nephi 2:5, there are three more examples of variation:
For these three examples, the original manuscript scribe was the unknown scribe 2, while Oliver Cowdery was the scribe for the printer’s manuscript. For 1 Nephi 2:5, Oliver Cowdery was the scribe for both 𝓞 and 𝓟. In all four of these cases, we let the earliest textual sources determine the correct reading since either brothers or brethren is semantically possible.
The spelling brether(s), used by both Oliver Cowdery and scribe 2 of 𝓞, apparently stands for brother(s). Besides the examples listed above, we have three other cases (all in 𝓞) where Oliver wrote brether(s) for brother(s):
The standard pronunciation for brethren is /bredrßn/, but under the influence of brother(s) /br^dßr(z)/, the first vowel of brethren is often pronounced with a centralized /^/ vowel rather than /e/ (as in /br^drßn/, my own pronunciation). The final r in brethren may also be vocalized, thus ending up with the pronunciation /br^dßrn/. This vocalization is due to the vocalization of the final r in brother(s). And finally, it is possible that both the final r and n may be vocalized, giving the three-syllable pronunciation /br^dßrßn/ for brethren.
The manuscript misspelling brether(s) for brother(s) is a reversal in the spelling of brother(s), apparently due to the pronunciation /br^dßrn/ for brethren. We also find evidence for this interference between brother(s) and brethren in terms of the vocalization of the final r in brethren. Consider, for instance, the statistics for these misspellings of brethren in the manuscripts and early editions:
| bretheren | 1 time | Oliver Cowdery in 𝓞 |
| 1 time | scribe 3 of 𝓞 | |
| 2 times | scribe 2 of 𝓞 | |
| 2 times | Hyrum Smith in 𝓟 | |
| 1 time | 1849 edition | |
| brethern | 3 times | 1830 edition (one corrected in-press) |
| 2 times | 1840 edition | |
| 11 times | 1841 edition | |
| 1 time | 1849 edition |
Summary: Each choice between brothers and brethren in the text should be determined by the reading in the earliest textual sources; based on the original manuscript, 1 Nephi 2:5 should read “and my elder brethren”; the misspelling brether(s) always represents the word brother(s), not brethren.