1 tc The Hebrew text has the plural, “letters.” The final mem (ם) may be dittographic (note the initial mem on the form that immediately follows). Some Greek and Aramaic witnesses have the singular. If so, one still has to deal with the yod that is part of the plural ending. J. N. Oswalt refers to various commentators who have suggested ways to understand the plural form (Isaiah [NICOT], 1:652).
2 tn In the parallel text in 2 Kgs 19:14 the verb has the plural suffix, “them,” but this probably reflects a later harmonization to the preceding textual corruption (of “letter” to “letters”).