I can't speak for anyone else, but I do have an advanced degree in a field that makes me qualified to judge what Joseph produced as "Reformed Egyptian", and I find it to be nonsense.
There is absolutely zero evidence that Reformed Egyptian ever actually existed, and for the time period that the BOM supposedly covers, we know exactly what forms of Egyptian were being used where. "Reformed Egyptian" is not among them. This is not a matter of opinion at all, and even if it were, mine is informed by
actual research in the field (I did my MA thesis on Coptic, the only form of Egyptian that is still used today), not by an 19th century religious text that is claimed to be miraculous. Linguistics is a science, not a religion, so as a science it is constrained by the need for evidence to support its theories and conclusions. Again, there is no evidence that Reformed Egyptian existed, so scientifically-speaking, it is a non-entity. Unless such evidence somehow arises (which will naturally need to be vetted by disinterested/not religiously-motivated actual linguists, not LDS shills like those who teach at BYU and other Mormon-run institutions), this will remain the state of things.
This is Egyptian:
(The Ebers Papyrus, c. 1550 BC, detailing the treatment of asthma)
And so is this:
(Ostracon with Demotic inscription from the Ptolemaic period, c. 305-30 BC, containing a prayer to Amun to heal a man's blindness)
And so is this:
(Coptic Gospel according to St. Luke, 5:5-9, 8th century AD)
This is demonstrably
not Egyptian:
(Anthon Transcript/"Caractors" Document, 1828)
This is not a matter of opinion, but a matter of
fact. Joseph Smith's creations are obvious to anyone with even a modicum of contact with the Egyptian language. I'm being completely serious right now (i.e., this is not me being "anti-Mormon", but telling what my academic training obliges me to tell) when I say that there is absolutely zero linguistic basis for considering this any kind of Egyptian whatsoever. It's simply fabricated. It does not reflect any stage, type, or dialect of the Egyptian language in any way (it is questionable whether or not it reflects
any known language). Joseph clearly knew no Egyptian, and this sort of writing (or the supposed Egyptian grammar that was attempted by a circle of his followers sometime later) does nothing to substantiate the idea that he did, which is a
religious belief of the Mormons, not a scientifically valid observation or hypothesis (as it cannot be falsified, since it's not actually based on evidence, but on religious conviction). Period. End of story.