Check Which YouTube Videos have Manual Closed Captions
YouTube’s automatic captioning of videos – or ‘subtitling’, as we say in the US and UK – is one of the site’s most useful features, especially if you’re hard of hearing or are watching with the sound off. However, not all videos have subtitles – perhaps due to poor sound quality or because the creator has turned them off–and others may offer ‘closed captions’ in several languages.
A new add-on called YouTube Caption Indicator (Download Now) addresses this by adding language-specific subtitle indicators to every video that appears in the ‘Up next’ list. Just look for the ‘CC’ next to the video to see whether closed captions have been generated automatically, transcribed manually in English or another language or don’t appear at all. You’ll still have to click the Subtitles button on the video’s menu
bar to activate the option.