In my previous post, "The Smoking Gun for Joseph's Translation of the Book of Abraham, or Copied Manuscripts from an Existing Translation?," I suggested that examination of the "smoking guns" for Joseph's alleged "translation" process in creating the Book of Abraham actually don't reflect an author creating and dictating a revealed text, but appear to reflect two scribes seeking to make a copy of an existing document. The process began orally, with somebody, possibly one of the scribes, reading an existing text out loud as both scribes then copied what was read. Then Warren Parrish quit writing at and that point, the manuscript by Frederick G. Williams shows that his copying process probably became based on looking and writing rather than listening and writing, evidence by an accidental repeat of three verses of text. If Williams were reading the text for Parrish's benefit, or if a third party were reading it for both of the scribes, when Parrish left, there would be no need to keep reading, and Williams could simply copy the text directly by hand. 

If Williams were the speaker, as I proposed, and had the text before him, he would have had the benefit of seeing how unusual names were spelled, and thus would be less likely to introduce misspellings that needed correction when it came to proper names. So let's look at the typos in proper names in these two manuscripts and see how they compare. I awoke with this idea and did not know what the results of the inquiry would be as I wrote the above text. So let's see how my hypothesis holds up.

Here are the proper names in each manuscript, excluding Egypt and Egyptian, Ham, Adam, and Noah. They are shown in order and grouped by name in order of occurrence and showing corrections:

The transcript of Manuscript A by Frederick G. Williams has these proper names, shown in order of occurrence but grouped by name, with corrections shown:

• Elk=Kener, Elk=Kener, Elk=Keenah, Elk-keenah, Elk Kee-nah, Elk-Keenah, Elkkeenah
• Zibnah, Zibnah, Zibnah
• Mah-mackrah, Mah-Mach-rah, Mah-Mach-rah
• Pharoah, Pharaoh, Pharaoh, pharaoh, Pharaoh, Pharaoh, Pharaoh, Pharaoh, Pharaohs
• Chaldea, Chaldea, Chaldeea, Chaldea, Chaldea, chaldees, chaldees, chaldees
• Chaldeans, Chaldians, Chaldea ["in the Chaldea signifies Egypt" - Chaldean is meant]
• Potipher<​s​> hill, Potiphers hill
• Olishem
• Onitus Onitah
• Kah-lee-nos [note that the canonized text has Rahleenos]
• Abram, Abram, Abraham <​Abram​>, Abram, Abram, Abram
• Ur, Ur, Ur, Ur, Ur
• Cananitess, cannites
• Zep-tah
• Egyptes
• Haran, Haron, Haran, Haran, Haran, Haran, Haran
• Terah
• Sarai, Sarai, sarah
• Nahor
• Milcah
• canaan, canaan
• Lot 

Manuscript B by Warren Parrish has these proper names showing corrections, as displayed in the transcript at the Joseph Smith Papers site:

• Elkkener, Elkken[er][here the edge of the paper is damaged obscuring the final r, but it appears that he wrote the full word, Elkkener], Elkkener, Elkkener, Elkkener, Elkkener
• Zibnah, Zibnah, Zibnah
• mahmachrah, Mahmachrah, Mahmachrah
• Pharoah, Pharao[h], Pharaoh, Pharaoh, Pharoaoh, Pharaoh, Pharaoh, Pharaoh, Pharaoh, Pharaoh, Pharaoh
• Chaldea, Chaldea, Chaldea, Chaldea, Chaldea, Chaldeas
• Chaldeans, Chaldeans, Chaldea ["in the Chaldea signifies Egypt" - Chaldean is meant, same error here as in Manuscript A], 
• ​Shagreel​, Shagreel
• Potiphers hill, Potiphers hill
• Olishem 
• Onitah
• Kahleenos [The canonized text has "Rahleenos." Since a cursive capital R often looks much like a K, it would be easy to read "Rahleenos" on an existing text as "Kahleenos." Williams also wrote "Kahleenos." Perhaps the original text had Kahleenos, or it may have had "Rahleenos" which Parrish or someone else misread.]
• Abram, Abram, Abram
• ur, Ur, Ur
• canaanites, Canaanites
• Zeptah
• Egyptes
• Haran, Haran
• Terah 
• Sarai
• Nahor
• Milcah

Parrish is not a great speller, giving us "preist," "sacrafice," "fassion" (fashion), "patraarch," "govermnent," "pople" (people), "Idolitry," "deliniate," "runing," and "smiten," but he spells names consistently, with the exception of capitalization and one typo for Pharaoh. Williams, on the other hand, has significant variation in his spelling of unusual words, suggesting that he was writing down what he heard for the most part, while Parrish might have been looking at what he was writing or was able to see it when needed if someone else were dictating, so his unusual words are spelled accurately and consistently.

Based on the data, it seems unlikely that Williams was reading the text, but much more likely that Parrish was, or that he could at least see the text when needed to see how unusual names were spelled. My original hypothesis (Frederick G. Williams as a possible reader) is overturned.

Update, April 19, 2019: When Warren Parrish wrote the third Book of Abraham Manuscript, Manuscript C, the transcript at the Joseph Smith Papers says he wrote "Rahleenos." I think this is a mistake. It certainly looks like Rahleenos at first glance, but in the same verse, the way Parrish writes "K" in "King" is identical to the letter that is followed by "ahleenos." In other words, it's clear that he also wrote Kahleenos. There are no capital Rs in that document to see how he would have written Rahleenos, but you can see many capital Rs in other documents such as his "Minutes, 3 September 1837" at the Joseph Smith Papers site. His capital R is much different than his capital K. Is our current "Rahleenos" an error or does it reflect what was on or should have been on the original but missing document from Joseph's translation of the Book of Abraham? When Rahleenos appears again in an 1842 manuscript from Willard Richards, that "R" looks an awful lot like the "K" in the word "King" shortly before it, but there is an touch of extra ink in that "K" that distinguishes the two. He joined the Church too late to be involved in the early Book of Abraham work, but it shows that in handwriting of that era, it was possible for a "K" and an "R" to look quite similar. Curious to know what Joseph originally dictated.