Reference: Verse 25 reprises Isaiah 29:13: “Wherefore the Lord said, Forasmuch as this people draw near me with their mouth, and with their lips do honour me, but have removed their hearts far from me, and their fear towards me is taught by the precept of men.” Nephi has made only a few changes in Isaiah’s text. The most important, in verse 24, resets the prophecy from Isaiah’s context of a straying Judah to an apostate Gentile world in the last days.
Variant/Translation: Some of the changes in the text from KJV Isaiah are consistent with a scenario of dictation from a source that is not being read precisely. Notice the addition of an “s” to “heart(s)” and “toward(s).” These changes cannot come from the written KJV text, and have no informational purpose. Because so much of the translation shows evidence of a loose connection between the English and the plate text, it is unlikely that such subtle changes are due to the plate text. They are, however, consistent with a shift from the more formal language of the KJV to a more colloquial reading, most likely Joseph’s dictation to Oliver Cowdery. While either one of them could have added the “s” in either or each case, I assume that the language is more likely Joseph’s.
Assuming that Joseph added the “s,” he either was not directly reading from a King James Version text or was not doing so with precision. Adding the “s” to “heart” seems like an attempt to pluralize “heart” to match the plurality suggested by “people.” That change could occur only if Joseph were mentally processing the information as he read, rather than mechanically reading word by word.