Japanese women's language has a long history. At first, it was created by women themselves. Its important characteristic was the avoidance of Chinese words. As time went on, men took advantage of women's language to condition women. For the most part, contemporary women's language was established in the Meiji period, reflecting prewar values. Therefore women's language has traits such as a higher level of politeness than men's language, sentence final particles to soften the statement, and avoidance of assertive and imperative forms and of derogatory expressions. Women born after the war, who were educated based on the ideal of sexual equality, began to feel awkward using women's language. Evidence of gender difference in language was obtained from the analyses of survey results and of two TV programmes. Most feminine expressions are used predominantly by women, and most masculine expressions are used predominantly by men. Women use politer expressions than do men in the situations surveyed. However, some contrasting tendencies were also demonstrated. Two feminine expressions which strongly demonstrate femininity (no when used with polite forms, and kasira) are not used by many women. Two masculine expressions which do not have derogatory connotations but function to show solidarity, dekkai and umai, are used by many women. One feminine expression which has emotional function but does not sound feminine, Ussoo!, is used by many men. Women's and men's social roles are beginning to overlap, so too therefore are women's speech and men's speech. From comparisons of the results between Japan and New Zealand, it was verified that in general women's speech is less feminine and men's speech is less masculine in New Zealand compared with that in Japan. This would appear to be a result of the influence of New Zealand society, in which gender difference in social roles is small and there are many mixed-sex interactions. As far as ways to ask a favour of a person are concerned, generally speaking, both women and men in Japan use politer expressions than women and men in New Zealand, respectively. This would appear to be a result of the strong reflection of the importance attached in Japan to conforming to social conventions (a phenomenon labelled "discernment" by some authors, and called wakimae in Japanese). It was certified that most women and men in both Japan and New Zealand regard women's language as necessary. Even though the gender difference in roles is becoming smaller, there is little possibility of the gender difference in language disappearing, as well as the gender difference in social roles in Japan. This is because wakimae is deep-rooted in Japanese people's minds. It seems likely that, in the future, stereotyped feminine expressions which demonstrate femininity, and masculine expressions which have derogatory connotations, will be abandoned. However, Japanese people will leave the gender difference in language to a certain extent, because of their desire for discernment.