The calendar grid's header row and the week-start toggle label were the only text in the shell that followed the system locale, so a German desktop drew MO DI MI over an interface that is English everywhere else. Nothing chose that; they were the only two places reading day names off Qt.locale(). Take them from en_US instead. Where the week starts still follows the locale: that is a regional convention rather than a translation, and it stays overridable through weekStartDay. Dropping the trailing-period strip with it, since that existed only for the locales this no longer renders. Co-authored-by: Claude Opus 5 <noreply@anthropic.com>