"Changing English" is a new feature in "ELT Journal" which aims to illustrate the diversity of English in the world today and to ask whether, and how, ELT practitioners might accommodate such variation. Focusing on a particular language issue in each article, the series will explore how English varies between places and spaces, over time, and between groups of speakers, and will reflect upon the possible implications of this for ELT practitioners. The feature is edited by David Baker; David also provides our first article, which discusses "tag questions" in English and in ELT.