English: “That are not pure” — R’ Yehoshua ben Levi said: A person should never utter an unclean expression from his mouth, for Scripture twisted eight letters rather than utter an unclean expression, as it is said “of the pure animal and of the animal that is not pure” (instead of simply “the impure animal”).
On the daf / in context: The longer circumlocution “asher einennah tehorah” is preferred over the shorter “teme’ah.” The Torah itself models refined speech even when referring to the impure category.
Type of Learning
Custom (lesson in refined speech drawn from the Torah’s own circumlocution).
What Is Learned
One should avoid unclean language; the Torah itself lengthens the phrase rather than say “teme’ah.”