The paper asks whether six ongoing vowel changes in Philadelphia English show interspeaker covariation. In a sample of 66 young white women, pairwise correlations are significant only between three changes that have previously been observed to show parallel diachronic trajectories of change reversal, whereas changes that do not exhibit this diachronic pattern do not show covariation. I propose that the interspeaker covariation in this subset of the changes in progress arises from a shared social motivation for the change reversals that is not shared by the other changes.

中文翻译：

---

费城元音变化中的语际协变

该论文询问费城英语中六个正在进行的元音变化是否显示出语者间协变。在 66 名年轻白人女性的样本中，成对相关性仅在先前观察到的三个变化之间显着，以显示变化逆转的平行历时轨迹，而未表现出这种历时模式的变化不显示协变。我认为，在这部分正在进行的变化中，说话者之间的协变源于对变化逆转的共同社会动机，而其他变化不具有这种动机。