This verse is both extremely important and extremely difficult to completely understand. Nephi says that he is making a record “in the language of my father.” That is a strange statement. Most of us speak “the language or our father.” We learn to speak in the home, and learn to speak the language we hear. It is the language of our fathers, and is so unremarkable that we need not mention it. Yet Nephi does.
When he clarifies that his father’s “language” “consists of the learning of the Jews and the language of the Egyptians” we don’t find that clarifying statement as illuminating as he possibly thought it was.
One suggestion is that he is speaking of using the Hebrew language, but writing in Egyptian characters. This is a possibility, as documents from antiquity exist that demonstrate that very merger of two different cultures. Also, both Hebrew literature and the Egyptian language were taught in Hebrew scribal schools.
In any case, there is something about Egyptian that continues throughout Nephite written history. Late in the text, Moroni says that their characters are “reformed Egyptian.” That strongly suggests that some form of Egyptian writing came to the New World with Nephi. That writing system need not have been hieroglyphs. Hieratic script had been in use long before Nephi’s day, and the Demotic script was invented close to Nephi’s time. Given the timeframes, Hieratic would be the better guess for the script Nephi learned.
Egyptian writing systems were syllabic. That is, a character represented a syllable, not a single sound as in our writing system. Thus, three different characters would represent ba, bo, and bu. Our writing system uses six characters. It may or may not be connected, but the only known writing systems in the New World are also syllabic. That isn’t to say that they were created because of the Nephite importation of Egyptian, but that there was a conceptual similarity that might explain the way in which the original Egyptian might have been reformed using more culturally relevant representations for sounds.