Joseph Smith had a very difficult time distinguishing Hebrew names from Greek and Latin ones. One of his biggest blunders shows up in Doctrine and Covenants 110, which reccounts the supposed visitations to Joseph and Oliver Cowdery in the Kirtland temple. In verse 12 Joseph says "Elias appeared, and committed the dispensation of the gospel of Abraham, saying that in us and our seed all generations after us should be blessed," which sounds totally cool and only slightly confusing (why's Elias officiating for the gospel of Abraham, and what the hell is Abraham's gospel anyway?). The problem occurs in the next verse when "Elijah the prophet, who was taken to heaven without tasting death, stood before us." The problem is that Elias is the Romanized Greek version of the Hebrew name Anglicized as Elijah. In other words Elias and Elijah are the same person, the former spelling of his name appears in the New Testament and the later form is found in the Old Testament.
LDS Church leaders have since decided that (1) there must have been some other prophet out there during Abraham's time named Elias (a Greek dude was hanging around with Abraham?) and that (2) Elias is probably a title for a forerunner prophet. I'm not making this shit up.
The more likely possibility seems to be that Joseph just didn't know the difference between Hebrew and Greek versions of the name in question.
Corroborating evidence to this latter theory is found in The Book of Mormon when Nephi uses the terms "Messiah," a Hebrew term, and "Christ," a Greek term - both literally meaning the anointed - in the same verse. Twice. Isn't that amazing? Nephi, a Hebrew is using messiah correctly (as a title) but using the Greek word Χριστός as Jesus' proper name. Nephi and Joseph need some serious help with their Greek.
Not that their Hebrew was any better. In 3 Nephi Jesus gives the Nephites chapter four of Malachi and the Nephites write down that "the Son of Righteousness" shall arise whereas Malachi wrote about "the Sun of righteousness." Now unless Jesus was speaking to the Nephites in English, it would have been very difficult for them to hear shamesh (Hebrew for sun) and then write down ben (Hebrew for son). What are the chances that Joseph's scribe screwed things up and the mistake going uncorrected all these years? What are the chances that Joseph thought he was being clever and screwed up?
The Book of Mormon also inserts the use of synagogues "after the manner of the Jews" in Nephite America even though synagogue worship did not exist at the time Lehi left Jerusalem. So where did the Jewish synagogue practice come from? Might Joseph have imposed New Testament era Jewish worship on people who would have been entirely ignorant of those practices?
"Just because we'll be living in the New World without any kind of telecommunicative technology doesn't mean we won't know exactly what our fellow Jews are up to in several hundred years."
Well how about Jews going to church? Laban and Zoram, two Jews living ca. 600 B.C.E., apparently were church goers, if that makes sense at all. It seems as though Joseph really liked Hellenizing his Hebrews.