Why in 2 Nephi 29:6 would Nephi have used the word Bible?
Nephi would not have used the word “Bible”. He would not have used any English words at all. Nephi did not speak English, but a dialect of ancient Hebrew. Whatever word Nephi actually used that ended up engraven on the gold plates, the translator of those plates rendered the idea behind that word by using the term “Bible”, a word that in English perfectly represents the thought.
Our word “Bible” derives from the Greek word βιβλία (biblia), a plural noun meaning “little books”. And that is exactly what the Bible is; a collection of books. It’s a whole library of sacred texts, all gathered together. Nephi saw in vision that these sacred texts would be collected into one invaluable book, a volume of scripture similar to his own brass plates of Laban, “save there are not so many [scriptural writings in the Bible as there were on the brass plates].” There can be no doubt that Nephi is referring to our very Bible in these verses. So the translation of Nephi’s thought as “Bible” is not merely linguistically correct, it’s literally the very thing that Nephi was trying to express.