While the near-ubiquity of interrogative intonation instead of traditional declarative intonation in subordinate clauses in the speech of young females has often been remarked, it now needs to be observed that this feature has begun spreading to the speech of young males, and not just adolescents. (It is also occasionally appropriated by not-so-young females in a pathetic effort to sound girlishly modern, as in the off-putting patois of the NPR interviewer Terry Gross.)
Although it is clear that the substitution of interrogative for declarative intonation can have the function of communicating the indecisiveness or unsureness of the speaker in making an assertion (“do you follow me?,” “do you know what I’m saying?” also being implied), there is also a more general meaning attaching to this kind of change in intonation pattern. The deployment of the interrogative where no explicit question is being asked is tantamount to conceding in advance the rightness or force of an assertion, analogous in its purport to the typically feminine apotropaic smile that is so common in American culture. In this respect, younger males are only belatedly mimicking the self-protective tactics known to women from the beginning of time, and of increasing utility to both sexes in a milieu where predisposing or maintaining anodyne interpersonal relations is of superordinate value.