Ketubot, Chapter Seven, Mishnah Six
The first five mishnayoth of this chapter referred to situations in which a husband must divorce his wife and pay her the ketubah. In this mishnah we learn situations in which a husband has grounds for divorcing his wife and not paying her ketubah. These situations refer to cases in which the woman has not behaved in a proper manner, either directly with her husband or with outside society.
1) These leave [their marriage] without their ketubah:
a) A wife who transgresses the law of Moses or Jewish law.
2) And what is the law of Moses?
a) Feeding her husband with untithed food, having intercourse with him while in the period of her menstruation, not separating dough offering, or making vows and not fulfilling them.
3) And what is Jewish practice?
a) Going out with her head uncovered, spinning wool in the marketplace or conversing with every man.
4) Abba Shaul says: also one who curses her husbands parents in his presence.
5) Rabbi Tarfon says: also one who has a loud voice.
a) And who is regarded as one who has a loud voice?
b) A woman whose voice can be heard by her neighbors when she speaks inside her house.
Section one: The mishnah describes two categories of women whose husbands may divorce them without paying their ketubah: the one who transgresses the Law of Moses, which is interpreted to mean she causes her husband to transgress the Law of Moses, and the second is the one who transgresses Jewish law, which means she engages in immodest behavior.
Section two: The mishnah now lists four ways in which a wife might cause her husband to transgress. If she does not separate the tithes or the dough-offering (hallah) her husband will eat forbidden food. She has a responsibility to tell her husband when she is in her period of menstruation and if she does not and he has relations with her, he too is a transgressor. The fourth category is somewhat less clear, for we would not imagine that the husband transgresses if his wife does not keep her vows. The Talmud explains that children die as a result of broken vows and therefore she is injuring him as well. A simpler explanation may be that since the husband has the right to annul his wifes vows, he too is held responsible if she doesnt keep them.
Section three: This section lists certain immodest actions that are grounds for divorce. In Talmudic times women did not go out without their heads covered (for that matter, men also usually covered their heads). Spinning in public was also considered unbecoming, perhaps because the woman would uncover her arms while spinning. Talking with many strange men was also considered improper behavior for a married woman. Since the woman engaged in one of these behaviors, her husband may divorce and not pay her ketubah.
I might add my personal opinion that what was improper behavior must have been determined by norms in the larger society, at least to a large degree. Since it was normal for women to cover their heads, Jewish women who did not were immodest. I do not think that this implies that not covering ones head is inherently immodest. However, other Jews might disagree with me.
Section four: Abba Shaul adds that a womans cursing her husbands parents in front of him is also grounds for divorce.
Section five: Rabbi Tarfon adds that a woman whose voice is too loud, that is she can be heard by her neighbors from inside her home, may also be divorced without a ketubah. The Talmud teaches that this refers to a woman who talks about sex too loudly.