Comentario citado sobre Isaías 44:21

You have neglected from “you shall not be forgotten” [Isaiah 44: 21]. Here the letter following the tav is missing, with a dagesh taking the place of an absorbed nun , and also with a yod in place of a heh (as in “do not blot out” [Jeremiah 18: 23] — both these words are accented on the penultimate, to distinguish the second person masculine singular future from the second person feminine singular future of an unaspirated lamed-heh verb) — although in my opinion the yod is simply extraneous, as the verb could have been conjugated as in “do not fail the words of my mouth” [Proverbs 4: 5].

נשני, the construction of the word from the root נשש is similar to a similar construction of the root חנן in 33,11 where Yaakov explained to his brother Esau that he was looking at his children. The proof of this is the dagesh in the letter ש. [which effectively doubles that letter. Ed.] If the word nashani had been derived from the root נשה as in Isaiah 44,21 לא תנשני, or as in Lamentations 3,17, נשיתי טובה, where the root is one that loses its last root letter, the Torah here should have written nishani, instead of nashani. It then would have been parallel to the construction in Samuel II 19,27 עבדי רמני, rimani from the root רמה, to deceive, and other similar examples.