Connection between foul language and poor lineage: Pesachim 3b
Use of disgusting words in ordinary [non-holy] speech: Pesachim 3a
Choice of extra words vs. foul speech: Pesachim 3a-3b
Divine Punishment of Children, where the Parents are guilty of foul speech: Ketuvot 8b
Foul Speech causes Divine Termination of a 70-year Prescription for Life: Ketuvot 8b
Lishna Mialya Nakat - Using Clean/Superior Language
"Achilah [eating]" to refer to sexual relations: Ketuvot 13a, 65b
"Asher Lo Tahor [Not Pure]" in place of "Tamay [Impure]": Pesachim 3a
"Asiyat Tzerachim [Doing one's Needs]" to refer to sexual relations: Pesachim 109b, 110a
"Atzmo [Self]" rather than refer directly to Heaven in a negative way: Berachot 14b
"Aveirah [Transgression]" to refer to Sexual sin: Rosh HaShanah 17a
"Avdo [one's eved]" referring to paying someone for illicit sexual relations with his female eved; the Talmud refers to it as occurring between the two avadim: Temurah 29a, 30a
"Bait Yazek" instead of "Bait Yazek," place of chaining, where the witnesses who testified on the New Month stayed, if they arrived on Shabbat: Rosh HaShanah 23b
"Cheder/Prozdor/Aliyah [Various Rooms]" in discussing sections of the female genitalia: Niddah 17b
"Davar Acher [Another Matter]" for sexual relations: Berachot 8b, Yevamot 109a