Improve default subtitle language selection (#6240)

Authored by: sdht0

yt_dlp/YoutubeDL.py

@@ -2810,10 +2810,14 @@ class YoutubeDL:
                     self.params.get('subtitleslangs'), {'all': all_sub_langs}, use_regex=True)
             except re.error as e:
                 raise ValueError(f'Wrong regex for subtitlelangs: {e.pattern}')
-        elif normal_sub_langs:
-            requested_langs = ['en'] if 'en' in normal_sub_langs else normal_sub_langs[:1]
         else:
-            requested_langs = ['en'] if 'en' in all_sub_langs else all_sub_langs[:1]
+            requested_langs = LazyList(itertools.chain(
+                ['en'] if 'en' in normal_sub_langs else [],
+                filter(lambda f: f.startswith('en'), normal_sub_langs),
+                ['en'] if 'en' in all_sub_langs else [],
+                filter(lambda f: f.startswith('en'), all_sub_langs),
+                normal_sub_langs, all_sub_langs,
+            ))[:1]
         if requested_langs:
             self.to_screen(f'[info] {video_id}: Downloading subtitles: {", ".join(requested_langs)}')