The gemoro quotes a posuk in Yeshaya 9 to show that Nivul Pei causes terrible punishments. Yet that posuk also lists two more aveiros responsible for the same punishments, mainly ; Chonaf and Mera. Why does the gemora omit them for the cause of these punishments ? The Maharsha does ask the question, but I couldn't understand his answer. Maybe you can explain it, or offer another answer.
(a) See the RIF in the Ein Ya'akov, who may be saying the same answer as the Maharsha. The Rif suggests that granted, the death of Bachurei Yisrael and the cries of the orphans and widows come as a result of all of the Aveiros mentioned in the Pasuk. However, "Tzaros Ra'os v'Rabos Mischadshos" comes only as a result of Nivul Peh. This is derived from the last part of the Pasuk, which the Gemara understands is referring back only to Nivul Peh (and not to Chanef and Mera).
However, this does not conform to Rashi's explanation, that the punishment of Tzaros is derived from the first part of the Pasuk, "Bachurav Meisim."
(b) It could be that when the Navi mentions "Chanaf" and "Mera," he is referring to one who speaks Nivul Peh in order to be Mach'nif his fellow ("l'Hach'nif l'Mera'eihu"). "Re'ehu" in this context refers to his wife, as the Gemara uses the word in Kidushin 41a. As our Gemara points out, the example of Nivul Peh is, "Everyone knows why a Kalah goes under the Chupah....", and this is "Chanef u'Mere'a."
Be well, and stay in touch,
-Mordecai