וַֽיַּעֲמֹד֙ רַב־שָׁקֵ֔ה וַיִּקְרָ֥א בְקוֹל־גָּד֖וֹל יְהוּדִ֑ית וַיְדַבֵּ֣ר וַיֹּ֔אמֶר שִׁמְע֛וּ דְּבַר־הַמֶּ֥לֶךְ הַגָּד֖וֹל מֶ֥לֶךְ אַשּֽׁוּר׃
Then Rab-shakeh stood, and cried with a loud voice in the Jews’ language, and spoke, saying: ‘Hear ye the word of the great king, the king of Assyria.
Sefer Daniel; Opportunity in Exile
Before Churban Bayit Rishon, our ancestors in Judea spoke Hebrew. During the siege of Yerushalayim, the Assyrian Ravshakeh addressed Jewish commoners in Hebrew, so they could understand his demeaning words (Melachim II 18:28). Jewish leaders asked him to speak Aramaic so that commoners would not comprehend his words (ad. loc. Pesukim 26).