diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index ce2030d28..999afc110 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -1151,7 +1151,7 @@ def _parse_smil_subtitles(self, smil, namespace=None, subtitles_lang='en'):
                 }
                 if type_ in SUBTITLES_TYPES:
                     ext = SUBTITLES_TYPES[type_]
-            lang = textstream.get('systemLanguage') or textstream.get('systemLanguageName') or subtitles_lang
+            lang = textstream.get('systemLanguage') or textstream.get('systemLanguageName') or textstream.get('lang') or subtitles_lang
             subtitles.setdefault(lang, []).append({
                 'url': src,
                 'ext': ext,