Isaiah 7:11 (King James Bible) ask thee a sign of the LORD thy God ask it either in the depth or in the height above
As noted in the discussion under 2 Nephi 15:29, there are several instances where it has been omitted from the long Book of Mormon quotation of Isaiah (in 2 Nephi 12–24). In most cases, the corresponding King James text has an italicized it, but here in 2 Nephi 17:11 the corresponding it in the King James Bible is in regular (roman) type. For a similar case, see 2 Nephi 20:17–18.
The original Hebrew for Isaiah 7:11 is difficult. Some have conjectured that the second word for ‘ask’ (spelled anomalously with an extra h at the end, as ¸s√lh) may actually be a form of the noun Sheol, with the meaning ‘to hades’ (that is, “ask thee a sign of the LORD thy God in the depth to Sheol or in the height above”). In fact, the Latin Vulgate translated it this way (as in profundum inferni). In the original Greek Septuagint, the word s¸√lh (whether as ‘ask’ or ‘to hades’) was ignored, although some later Septuagint versions added ‘into hades’. The King James use of it seems to correspond to the extra h at the end of the word, and perhaps that is why the pronoun it was not set in italics. But the h does not really mean ‘it’, so the original Book of Mormon translation is at least correct in the decision to ignore the it.
In any event, the 1830 typesetter added the it, probably by reference to his King James Bible. The critical text will restore the earliest reading (without the it). This example provides one more case where a function word was not italicized in the King James text but perhaps should have been; nonetheless the word was omitted in the Book of Mormon text. For another example, see the case of the omitted the before “king of Syria” in 2 Nephi 17:1.
Summary: Based on the earliest textual source (the printer’s manuscript), the it after the second ask in 2 Nephi 7:11 should be omitted.