Nephi structures his description in the form of a conversation. Certainly, this represents the exchange in the vision, although the specifics of the conversation might have differed somewhat from what Nephi recorded from memory—perhaps soon after, or even much later, when he wrote this account. Dialogue is an effective way to present information in a logical order and break up the basic narration.
The Spirit asks what Nephi desires. Of course, Jehovah would know the desire. This is not a request for information, but for Nephi to verbalize that desire. The questions do not give the Spirit new information, but perhaps make it more real for Nephi, and certainly more interesting for his readers.
The Spirit notes that Nephi believes in the “Son of the most high God.” This is an interesting picture into an older layer of Israelite religion. In Lehi’s day, there was still an understanding of the council of gods. The head of the gods was the Most High God, and Jehovah was his son. This understanding of two different gods (at least) was not seen as contrary to monotheism, because the concept of monotheism at that time was that there was only one god for Israel, and other nations had other gods, including many gods for one people.
In Hebrew theology, the Most High God remained in the heavens and was more distant. The God of Israel, the one with whom the Covenant had been made, was the son of the Most High God, known by tetragrammation [consisting of four letters in Hebrew].