Many speakers of current Australian English often use a high-rising intonation in statements. This usage, which has been termed Australian Questioning Intonation (AQI), has a nonpropositional, interactive meaning (checking for listener comprehension) and interacts with the turn-taking mechanism of conversation. A quantitative study of the use of AQI in Sydney reveals that it has the social distribution characteristic of a language change in progress: higher rates of usage among working-class speakers, teenagers, and women. Real time data confirm this, showing that the form was almost nonexistent in this speech community two decades earlier. The social motivations of this innovation are examined in terms of local identity and the entry of new ethnic groups into the community, and possible linguistic sources are discussed. The utility of quantitative methods in studying meaningful linguistic variables is demonstrated. (Australian English, language change in progress, intonation, sociolinguistic variation, social class, social motivation)