[southpark] add support for videos with english audio track(closes #21271)

youtube_dl/extractor/southpark.py

@@ -78,6 +78,10 @@ class SouthParkDeIE(SouthParkIE):
         'only_matching': True,
     }]
 
+    def _real_initialize(self):
+        lang = self._get_cookies('http://www.southpark.de/alle-episoden/').get('SPS_video_language')
+        self._LANG = lang.value if lang else 'de'
+
 
 class SouthParkNlIE(SouthParkIE):
     IE_NAME = 'southpark.nl'