I also meant to add that in the link provided, Mormon says that if the plates would have been larger, Hebrew would have been used - something to that effect.
The thing is, the hieratic form of Egyptian hieroglyps (which seem to be what the plates employed) would take up just as much, if not more, room than Hebrew. Hieratic was used by scribes as a sort of cursive form of writing to not only make writing go quicker, but to also take up less room on a given sheet of papyrus (it was a long process to make papyrus “paper” - the more you could write on a given sheet, the better - sort of like all the abreviations you see on employed by scribes on parchment).
There is no language called “reformed Egyptian”, but…if it was the writing being referred to, I could see that term possibly being used - i.e. hieratic could have been seen as a “reformed” way to write Egyptian. The thing is too that although Egyptian writing appears on virtaully every object (apparently people liked writing on things!), the average person would not have been able to read it; particularly hieratic - it was very specific to what school you went to to learn it. The hieratic of Alexandria doesn’t look quite like the hieratic of Memphis or Thebes. This is even more so for the “abreviated” form of hieratic called Demotic (it’s no wonder why in Helenistic times, scribes finally adopted a normal alphabet in the form of a variation of the Greek alphabet).