The Talmud several times emphasizes the importance of not utilizing unclean language, or “nivul peh” (Shabbat 33a, Pesachim 3a). The Midrash (Vayikra Rabbah, 24) traces this transgression to the biblical prohibition of “So that He will not see a shameful thing (ervat davar) among you” (Devarim 23:15), interpreting “ervat davar” as “ervat dibur”, or “shamefulness of speech”. (See Mesilat Yesharim, ch. 11). Somewhat differently, Rabbeinu Yonah (Sha’arei Teshuvah III, 230) groups this prohibition within the larger category of “lashon hara”.

The Kozaglover Rav (Resp. Eretz Tzvi, II, inyanim shonim 69) takes up the question of whether this prohibition is specific to Jews or perhaps is applicable to all of humanity. Working within Rabbeinu Yonah, he notes a statement of the Maharsha (Shabbat 33b) that implies the prohibition of lashon hara is binding only on Jews, thus suggesting that the same is true of nivul peh. Consequently, he finds difficult the implication of the Tanna D’Bei Eliyahu (ch. 15) that individuals and societies from the general world population have been punished for this offense throughout history. However, if one focuses on the Midrash’s derivation of the prohibition, it might be more readily understood, as the prohibition of arayot (sexual immorality) is applicable to the whole world under the Noahide code.