TT #753 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:09
Then his yevamah shall approach him in the presence of the elders, and draw his shoe off his foot, and spit in his face, and respond and say: “Thus shall be done to the man who will not build up his brother’s house.”
Torah Temimah points to Yevamot / Rambam.
TT lemma: כָּכָה.
כָּכָה – בַּלָּשׁוֹן הַזֶּה; מִכָּאן שֶׁצְּרִיכָה לוֹמַר בִּלְשׁוֹן הַקֹּדֶשׁ (לְדַעַת רַבִּי יְהוּדָה).
English: “Thus” — in this very language; from here that she must speak in the holy tongue (according to Rabbi Yehudah).
On the daf / in context: An alternative (or complementary) source for the requirement of Hebrew in the declaration.
Derash from “kakhah” requiring the precise formula in Hebrew.
The declaration must be recited in the exact biblical language (Hebrew).