TRANSLATE & LISTEN · PRACTICAL GUIDE
YouTube translation: subtitles, narration or an audio track?
For a Japanese video you want to understand in English, first decide what you need: words on screen, spoken translated captions, or an audio track already offered by the video. These choices solve different viewing problems.
CastReader · Reviewed:
Keep the original sound and read captions
Choose captions when you want to hear the original speaker while reading along. Start by checking whether the video has a CC button and a usable caption track. Captions depend on what is available for that video.
In the CastReader extension preview, choose English and enable Translate subtitles. Leave Read translation off if you only want the text. The Japanese-to-English recording shows the English caption appearing while the video continues.
YouTube Help: caption availability and controls
Watch translated captions appear →Hear the translated captions while watching
Choose caption narration when following written subtitles takes too much attention. After the English translation appears in the CastReader preview, enable Read translation. The synthetic voice reads the translated text and highlights the part being read.
This is caption-based reading. It does not reproduce the speaker’s voice, translate sound effects or create a new downloadable dubbed video. Incorrect or missing source captions can affect the translation and narration. Check a short section before settling into a longer video.
See the narration controls and real recording →Use an English audio track when the video offers one
Some YouTube videos offer additional audio languages. In the player, open Settings, choose Audio track, and select English if it is listed. Availability varies by video; changing the caption language alone does not select another audio track.
If the video already has an English audio track that suits you, you can use it directly. CastReader’s preview is a separate way to listen to translated captions on supported videos.
When the captions are in the wrong language
First check the source caption track in YouTube’s Settings → Subtitles/CC. Select the language actually spoken in the clip when that track is available, then set the translation target in CastReader. The source track and target language are different choices.
Try a short passage containing ordinary speech. If the source captions are already incorrect, changing the target voice will not repair their meaning. If the English captions are correct but silent, enable Read translation and check the sound troubleshooting guide.
Check translated text with no sound →When no usable captions are available
The CastReader preview needs captions it can read; it does not transcribe a video without captions or support live streams. Check another captioned video to separate a video-specific limitation from a setup problem.
If you already have the text of a short passage, paste it into the Japanese-to-English tool. You can compare the result and hear either language there, independently of the video.
Troubleshoot missing YouTube captions →