The 1837 edition dropped the definite article the in both examples of the phrase “in the Hebrew”, probably because in current English we usually say “in Hebrew” (and similarly for any other language). Here in Mormon 9:33, the use of the the is not that difficult since we would normally interpret “in the Hebrew” as an ellipsis for “in the Hebrew language” or “in the Hebrew tongue”. Yet as David Calabro points out (personal communication), the ellipsis more reasonably stands for “in the Hebrew characters” (that is, “in the Hebrew writing system”). He notes that in the preceding verse Moroni specifically refers to writing in reformed Egyptian characters:
So in verse 33, when Moroni refers to the Hebrew being altered, he could be referring to the Hebrew characters being altered rather than the spoken Hebrew.
In the King James Bible, we have examples of “in the Hebrew tongue” (six times), “in the Syrian tongue” (twice), and “in the Greek tongue” (once). There are also two examples of “in the Syrian language”. Even so, the head noun is sometimes ellipted, namely, in two examples of “in the Hebrew”; in these two cases, the ellipsis appears to refer to the spoken language since the verb is call:
It should also be pointed out that in one case in the King James Bible the definite article is lacking:
In this case, the ellipsis could be either characters or language. In any event, from the perspective of the King James style, “in the Hebrew” is acceptable in Mormon 9:33; the critical text will restore this usage.
Summary: Restore in Mormon 9:33 the definite article both times in the phrase “in the Hebrew” since such an expression is fully understandable and is also found twice in the King James Bible.