To begin with I found a problem with the second verse in the Book of Mormon:
"Yea, I make a record in the language of my father, which consists of the learning of the Jews and the language of the Egyptians." (1 Nephi 1.2, pg 1)
I find a number of difficulties with the aspect that claims that the ancient Israelites continued to speak Egyptian 600 years after the exodus from Egypt. I doubt the record of the Book of Mormon as their experience in Egypt was so bitter they would have avoided even the Egyptian language since it would revive the association of Egypt. This same thing happens today in the case of German Jews who survived the Holocaust. They avoid speaking German as a rule. Also, people who migrate from place to place when a change of language is involved, the language of the 'old country' is hardly spoken at all past the third generation. For the Book of Mormon to claim that there were Jews in Jerusalem who, 15 generations after the Exodus, were still speaking some form of Egyptian is rather much for me to believe. Also consider that no written fragments of any form of Egyptian have ever been found in Israel from the first temple Period.

The second difficulty occurred as the family in the narrative set up camp after a three-day journey into the Sinai wilderness:
"And it came to pass that he built an altar of stones, and made an offering unto the Lord." (1 Nephi 2.7, pg 3)
Here the problem is that individual altars for offerings and sacrifices were forbidden even before the Temple of Solomon was erected, and that centralized worship was the norm, and every Israelite at the time knew it. Yet the narrative passed this incident off without comment as if it was perfectly normal. This would not have happened if the author of the Book of Mormon actually lived in 600 BCE as the LDS Church claims.

The third difficulty occurs immediately afterwards:
"And it came to pass that when he had traveled three days in the wilderness, he pitched his tent in a valley by the side of a river of water. ..and when my father saw that the waters of the river emptied into the fountain in the Red Sea, he spake unto Laman, saying; 'O that thou mightest be like unto this river continually running into the fountain of all righteousness". (1 Nephi 2.6 pg 3)
It seems quite plain to me that the author had never been in the Sinai wilderness near the Red Sea. If he had he would have known that rivers in that area do nothing of the kind! They do everything but 'flow continuously'! They are strictly occasional events occurring when a winter cloudburst breaks forth. The result is that a tidal wave of water washes through the valleys, finishing within hours or a day. This is usually a violent surge of water capable of rolling boulders of several tons in weight. If any man stood in its way he would be swept away and drowned in seconds. No, friend, the pastoral river referred to in the narrative is not to be found in the Sinai, but in more temperate climes.

9:3 And, behold, this was also according to the words of the
Lord unto me when he did first appear unto me as the flame of
fire; yea, when the Lord did appear as fire upon the altar before
me. And, behold, it was also according to the words which were
written upon the Liahona, after the time of our murmuring in the
desolate wilderness of the desert of Arabia.

The claim that Israelites would not use Egyptian is clearly false. By the ninth to sixth centuries before Christ, Israelites used Egyptian numerals mingled with Hebrew text.

http://en.fairmormon.org/Book_of_Mormon/Anachronisms/Language/Reformed_Egyptian
Any comments on that?

@Abish

That valley with a continous flow of water marked as A on the Fairlds map ... it's 150-200 miles from Jerusalem. Kinda far for a 3 day journey.

I'm more interested in official mormon teachings.

It doesn't matter. Dale Baranowski said that there are no these kind of rivers in that land.
Fact: there are these kind of rivers in that land.

I don't think we will have official teachings on that. Official teachings are about things that important for our salvation. What is not important for our salvation is not priority.

I don't treat it as it is important to me. I don't justify anything. I just don't see a problem where Dale Baranowski sees it.

........I already posted comments on some of FAIRS exagerrated claims: http://exmormonforums.com/viewtopic.php?f=6&t=2334&p=35349&hilit=Papyrus+Amherst+63#p35349.
Any comments on those?