Note the difference between the opening verse of Nephi's version and the extant King James Version corresponding verse:
Isaiah 49:1 1 LISTEN, O isles, unto me; and hearken, ye people, from far; The LORD hath called me from the womb; from the bowels of my mother hath he made mention of my name.
There is no particular difference in meaning, except that the emphasis of Nephi's version is heavily on the separation, even more obvious than that of Isaiah. For Isaiah's audience, the extra information would carry little extra information. For Nephi and his audience, however, the extra information would have pierced them as surely as an arrow aimed directly at them.
Meaning for Isaiah's immediate audience: This is the call to the separated (both past and near future) of Israel. The address is not just to Jerusalem, but to the House of Israel. In the old world it would have been interpreted as those of the house of Israel carried away into captivity.
Meaning for Nephi's audience: Nephi, as indicated earlier, very clearly interprets references to the isles of the sea as a reference to the Lehites. When Isaiah calls "Listen, O isles, unto me, and hearken ye people from far..." it is certain that Nephi felt that the scriptures were aimed directly at them. This was no abstract call, this was a prophetic voice reaching over the years and distance to call the family to repentance.