Checklist

  1. Not in the list: add Sogou in system input settings;
  2. Wrong default language: put Chinese (Simplified) first with Sogou on top;
  3. Shortcut conflict: use Ctrl+Shift or Win+Space instead;
  4. Per-app English mode: click the status bar or press Shift;
  5. Framework or permission: authorise on Mac, use Fcitx on Linux;
  6. Disabled: re-enable it in system settings.

Last resort

Repair or reinstall the client — it usually restores shortcuts and status bar settings. Export your dictionary first.