The title’s foregrounding of clothes, by the way, is indicative but potentially misleading: clothing is but one of many topics whose metamessages Tannen analyses.
A chapter on inclusion and exclusion in female relationships notes the early emergence of this preoccupation:
Much of the talk that little girls exchange with their friends is telling secrets. Knowing each other’s secrets is what makes them best friends. The content of the secret is less significant than the fact that it is shared: Exchanging secrets is a way to negotiate alliances. A girl can’t tell secrets in front of girls who aren’t friends, because only friends should hear her secrets. So when girls don’t like another girl, they stop talking to her, freeze her out of the group. That’s why when a little girl gets angry at a playmate, she often lashes out, “You can’t come to my birthday party.” This is a dreadful threat, because the rejected girl is left isolated. In contrast, boys typically allow boys they don’t like, or boys with low status, to play with them, though they treat them badly. So boys and men don’t tend to share (or understand) girls’ and women’s sensitivity to any sign of being excluded. (They tend to develop a different sensitivity: to any sign of being put down or pushed around.)