Two dialog boxes using Deferreds?
First of all, always return def.promise() - not def itself. If you return the Deferred object itself, other code can call resolve/reject on it. So keep def to yourself, and only return its promise.

Also, why not use reject() for the Cancel buttons instead of resolve(false)? If you use reject, it'll probably make the rest of your code simpler, since you don't need to check the resolve arguments. Your "success" handler either gets called, or it doesn't.

Second, since you're building buttons in both cases, that'd probably be the part I'd extract. For instance

function makeDialogButtons(resolveTitle, rejectTitle) {
  var def = $.Deferred(),
      buttons = {};

  buttons[resolveTitle] = function () {
    def.resolve();
    $(this).dialog('close');
  };

  buttons[rejectTitle] = function () {
    def.reject();
    $(this).dialog('close');
  };

  return { buttons: buttons, promise: def.promise() };
}


And use it like so

LanguageLogosView.showConfirmEmptyRowsDialog = function () {
  var buttons = makeDialogButtons('Save', 'Cancel');
      options = $.extend(LanguageLogosView.dialogConfirmDefaultSettings, buttons.buttons);
  $("#dialog-confirm-save-with-empty-rows").dialog(options);
  return buttons.promise;
};


It's not great, but it should do the job.