What exactly were the Nephite interpreters?
These interpreters eventually ended up in the hands of Mosiah the younger, who used them to translate the Jaredite record — the Book of Ether. We don't know exactly how Mosiah acquired the interpreters. It's possible they were found with Ether's plates or that Mosiah was led to them by an angel. It's also possible that he received them from his grandfather, the first Mosiah.
Many years earlier, Mosiah 1 and several other Nephites had merged with the Mulekites in Zarahamela — which was the final resting place of Coriantumr, the last Jaredite king. Mosiah 2 eventually passed the interpreters to other Nephite prophets, and it seems they were included in the stone box with the Book of Mormon plates.
As the Book of Mormon translation came to an end, Oliver Cowdery, Martin Harris and David Whitmer asked Joseph Smith to ask the Lord if they could be witnesses to the record as foretold in Book of Mormon (see Ether 5:4 and 2 Nephi 27:12). The Lord replied that if they remained faithful they would see "the plates, and also ... the breastplate, (and) ... the Urim and Thummim, which were given to the brother of Jared upon the mount..." (D&C 17:1).
Because the Book of Mormon never uses the phrase "Urim and Thummim" we don't know if the Lord revealed this designation or if Joseph and the early Saints simply applied it on their own. Like any revelation, Doctrine and Covenants section 17 reflects the Lord's directives as articulated in Joseph's language.
The biblical references to the Urim and Thummim are a bit ambiguous, but modern scholars argue that according to ancient sources the Urim and Thummim was used for revelatory purposes and the term can be translated as "light" and "perfection." Several sources also tell us that they glowed.
While the Nephite interpreters would not have been the very Urim and Thummim from the Bible, they obviously operated in a similar fashion. They were used to receive revelation, and they glowed in the Jaredite vessels during the oceanic voyage (more on this in a future issue). We can see, therefore, that the term "Urim and Thummim" can refer to more than one item.
Abraham also had a Urim and Thummim whereby he learned about the cosmos (Abraham 3:1-4). Joseph Smith taught that the place where God resides is a "great Urim and Thummim" and the celestialized earth will become a Urim and Thummim. He also taught that the white stone mentioned in Revelation 2:17 will be an individual Urim and Thummim to all those who received one (D&C 130:6-11). The "white" stone may refer to the glowing nature of this device. In Joseph's day, the Urim and Thummim referred to more than one translating tool.
Today, when most members think of Joseph Smith translating the plates, they often envision Joseph on one side of a curtain while a scribe sat on the other side.
They also may envision Joseph translating the record in one of two possible scenarios: 1) Joseph looked at the plates with his natural eyes as a scholar would study an ancient manuscript, and — by way of revelation — was able to discern the interpretation of the text, or 2) Joseph looked into the Nephite interpreters — possibly holding them over the plates like a lens — and saw the English translation of the text.
From what we know from witnesses to the translation process, or those who had talked with Joseph about the process, however, there are several things wrong with and missing from these re-creations
First let's talk about the curtain. There was a curtain between Joseph and Martin Harris when Joseph copied some characters from the plates for Martin to take to Charles Anthon. Joseph had to look directly at the plates, and Martin was not authorized to view them, so a curtain was necessary.
During the actual translation, however, the only time a curtain was used was in a doorway on those occasions when they wanted to keep visitors from disturbing the prophet and scribe as they worked. In many instances the translation was done in the presence of others. Some parts of the Book of Mormon, for instance, were translated in the Whitmer home in full view of all those inside the house.
What did those witnesses see? Stay tuned for more on the means and method of the Book of Mormon translation.

100: Celebrating a Century of Recording Excellence — Mormon Tabernacle Choir
Return: Four Phases of Our Mortal Journey Home — Robert D. Hales
The Eternal Christ — Truman G. Madsen
Driven: An Autobiography — Larry H. Miller and Doug Robinson
Fishing: Observations of a Reel Man — John Bytheway
2010 Summer Playlist — Deseret Book Company
Heavensong: Music of Contemplation and Light — Mormon Tabernacle Choir
Then Sings My Soul — Jenny Oaks Baker
Song of Redeeming Love — Dallyn Vail Bayles
Fablehaven, Vol. 5: Keys to the Demon Prison — Brandon Mull
Book of Mormon Stories (Beginning Reader) — LDS Distribution Center
Knights of Right, Vol. 1: The Falcon Shield — M’Lin Rowley
Fablehaven Boxed Set, Vol. 1-3 — Brandon Mull
My First Book of Mormon Stories — Deanna Draper Buck