What is the issue of listening to nivul peh?

Question

Assuming it is forbidden to consume media (e.g literature, music, film) that contains nivul peh, is it the same issur as speak nivul peh, or it is it more related to “guarding yourself from all evil” (i.e bad thoughts, etc.)?

Answer 1

I do not know all that much about the prohibition of ניבול פה (neither speaking nor listening), but from a very cursory survey of sources available on Sefaria, it appears that speaking and hearing ניבול פה are forbidden for identical reasons.

See, eg, Messilas Yesharim 11:

עוד בענין זנות הפה והאוזן, דהיינו, הדיבור בדברי הזנות או השמיעה לדברים האלה, כבר צווחו ככרוכיא ואמרו (ירושלמי תרומות פ"א): ולא יראה בך ערות דבר (דברים כג): ערות דיבור זה ניבול פה.‏

Furthermore, regarding the matter of lewdness of the mouth and the ear, namely, speaking words of lewdness or listening to them, our sages already "screamed like cranes" saying (on the verse): "'there shall not be any indecent (Erva) thing among you' (Devarim 23:15) - this refers to lewdness of speech" (Yerushalmi Teruma 1:6).

And Kitzur Shulchan Aruch 115:6:

הרוצה לשמור את עצמו מחטא זה ישמור את פיו מניבול פה, משקרים, מרכילות, מלשון הרע ומליצנות, וכן ישמור את אזנו משמוע דברים כאלו, גם יהא זהיר לקיים נדריו ולא ירבה בדאגה. וגם יהא זהיר מהרהורים רעים. וקודם שהולך לישן יעסוק בתורה או יאמר ד' מזמורי תהלים הראשונים ויזהר שלא לישן בחדר יחידי.‏

If you wish to avoid this sin, guard your mouth against obscene language, lies, talebearing, slander, and mockery. You should also guard your ears from hearing such talk. You must also be careful to fulfill your vows, not to worry too much about things, and be careful to guard yourself against lewd thoughts. Before going to sleep you should study Torah or say the first four Chapters of the Psalms,7 and be careful not to sleep alone in a room.

Answer 2

Talmud Shabbat 33a

מאי ועוד ידו נטויה אמר רבי חנן בר רבא הכל יודעין כלה למה נכנסה לחופה אלא כל המנבל פיו אפילו חותמין עליו גזר דין של שבעים שנה לטובה הופכין עליו לרעה אמר רבה בר שילא אמר רב חסדא כל המנבל את פיו מעמיקין לו גיהנם שנאמר שוחה עמוקה פי זרות רב נחמן בר יצחק אמר אף שומע ושותק שנאמר זעום ה׳ יפול שם

The Gemara explains: What is the meaning of the phrase: But His hand is stretched out still? Rabbi Ḥanan bar Rava said: Everybody knows why the bride enters the wedding canopy. There is no secret revealed. Nevertheless, anyone who speaks vulgarly about it, even if they, on High, sealed for him a decree of seventy years of good fortune, they will reverse it to bad fortune because of this sin. And Rabba bar Sheila said that Rav Ḥisda said: Anyone who speaks vulgarly, they deepen Gehenna for him, as it is stated: “The mouth that speaks perversity is a deep pit: he that is abhorred of the Lord shall fall therein” (Proverbs 22:14), i.e., Gehenna is deepened for one who speaks vulgarly. Rav Naḥman bar Yitzḥak said: Even one who hears vulgar speech and is silent is punished, as it is stated: “He that is abhorred of the Lord shall fall therein,” even if he himself does not speak at all.

Answer 3

According to the Artscroll Yom Kippur Machzor's commentary on Viduy, which is mostly based on the Michtav Me'Eliyahu, at least one of the Al Chet passages refers to listening to nivul peh. The implication there is that it is assur, because otherwise there would be no need for repentance for it.

I don't have the source in front of me at the moment to quote directly, I'll have to update this answer later.