diff --git a/src/calibre/gui2/tts/macos.py b/src/calibre/gui2/tts/macos.py
index 6e16eb6eef..0d2b71767f 100644
--- a/src/calibre/gui2/tts/macos.py
+++ b/src/calibre/gui2/tts/macos.py
@@ -27,7 +27,7 @@ class Client:
         self.current_marked_text = self.last_mark = None
         self.dispatch_on_main_thread = dispatch_on_main_thread
         self.status = {'synthesizing': False, 'paused': False}
-        self.settings = settings
+        self.settings = settings or {}
         self.ignore_next_stop_event = False
         self.apply_settings()
 
diff --git a/src/calibre/gui2/viewer/tts.py b/src/calibre/gui2/viewer/tts.py
index 4f86528802..349549c306 100644
--- a/src/calibre/gui2/viewer/tts.py
+++ b/src/calibre/gui2/viewer/tts.py
@@ -64,7 +64,10 @@ class TTS(QObject):
     @property
     def tts_client(self):
         if self._tts_client is None:
-            self._tts_client = self.tts_client_class(self.backend_settings, self.dispatch_on_main_thread_signal.emit)
+            settings = self.backend_settings
+            self._tts_client = self.tts_client_class(settings, self.dispatch_on_main_thread_signal.emit)
+            if self._tts_client.settings != settings:
+                self.backend_settings = self._tts_client.settings
         return self._tts_client
 
     def shutdown(self):