A Common Misconception
The terms "subtitles" and "captions" are frequently used interchangeably — especially outside North America — but they serve meaningfully different purposes. Getting this distinction right isn't just a matter of terminology: it directly affects whether your content is truly accessible to deaf and hard-of-hearing audiences.
What Are Subtitles?
Subtitles are text transcriptions of the spoken dialogue in a video. They assume the viewer can hear the audio but may not understand the language — for example, a French viewer watching an English-language film with French subtitles.
Standard subtitles typically include:
- Spoken dialogue
- Translations of on-screen text (signs, labels)
- Song lyrics (sometimes)
They do not typically include non-speech audio information like sound effects, music descriptions, or speaker identifications.
What Are Closed Captions?
Closed captions (CC) are designed for viewers who cannot hear the audio. They transcribe not just speech, but all meaningful audio in the video. The "closed" refers to the fact that they can be turned on or off by the viewer (as opposed to "open captions," which are always visible).
Closed captions typically include:
- All spoken dialogue
- Speaker identification (e.g., [REPORTER] or [JOHN])
- Sound effects ([door slams], [phone ringing])
- Music descriptions ([upbeat jazz music], [tense orchestral score])
- Tone/manner indicators where meaningful ([sarcastically])
What Are SDH Subtitles?
Subtitles for the Deaf and Hard of Hearing (SDH) are a hybrid format common on Blu-ray and streaming platforms. They include the same non-speech audio information as closed captions, but are delivered as a subtitle track (often in a different visual style). SDH subtitles can also be translated, making them useful for international accessibility.
Why This Distinction Matters
For a deaf viewer, a video with only standard subtitles can be a confusing or incomplete experience. Imagine watching a thriller where you can read all the dialogue but have no idea that an alarm is blaring, a helicopter is approaching, or that the character is whispering with urgency. Critical narrative information is lost.
Legally, this distinction matters too. Regulations like the Americans with Disabilities Act (ADA) and the FCC's captioning rules in the US — and equivalent legislation in the EU and UK — mandate that broadcast and online video content be made accessible through proper closed captions, not just subtitles.
Best Practices for Accessible Captioning
- Identify all speakers when more than one person is talking, especially if they're off-screen.
- Describe significant sounds — not every background noise, but any audio that contributes to understanding the content.
- Keep captions in sync with the audio. Delay of more than 2 seconds significantly reduces comprehension.
- Use accurate language. Don't paraphrase. Caption exactly what is said.
- Choose high-contrast text. White text on a dark semi-transparent background is the most readable combination.
- Maintain a reasonable reading speed — generally under 17 characters per second for broadcast content.
The Bottom Line
If your content is intended for a general audience — especially on public platforms — you should be providing closed captions, not just subtitles. The difference is not cosmetic. It's the difference between content that is accessible and content that excludes a significant portion of your potential audience.