This paper traces the development of a pre-modern speech variety known as nyooboo kotoba ‘court lady’s language’ and its role in the construction of normative language for Japanese women. I argue that what is today called joseego or onna kotoba (women’s language) originates in the attempt to regulate women’s speech in pre-modern Japan, in particular, the idea that the language of women in the imperial court (nyooboo kotoba) is gentle, elegant and, hence, feminine, and thus should serve as the ideal model of women’s speech. I also discuss the word formation processes used in nyooboo kotoba, which were believed at the time to render words refined and elegant. I then argue that these word formation processes share much in common with those of the modern wakamonogo ‘youth language’, which is considered rude and corrupt, and that this contradiction illustrates the subjective and ideological nature of these kinds of evaluations.