The Labovian 'Vanguard of Change' and 'Linguistic Conformity of Women' Principles (Labov 2001) are supplemented by an 'Epistemic Modality Principle' (stating that women are more prolific users of epistemic downtoners than men) and a 'Turn-Allocation Principle' (assessing that women use more completion signals than men in the negotiation of floor-apportionment). These principles are crucial in paving the ground for an explanation of gender differences in language. This volume is essential reading for those interested in language and gender and in how functionalism can be brought to bear in illuminating language structure and use.