SDH subtitling: what real accessibility requires

SDH stands for "Subtitles for the Deaf and Hard of hearing." They differ from standard subtitles on one central point: a deaf viewer doesn't just miss the dialogue — they miss the entire rest of the soundtrack too. SDH subtitling has to communicate in writing all the sound information relevant to understanding the scene, not just what the characters say.

What SDH subtitling includes that standard subtitles don't

• Speaker identification when it isn't obvious on screen (e.g. [MARIA])
• Description of sounds relevant to the plot (e.g. [footsteps approaching], [phone ringing])
• Indication of tone or music when it adds emotional information to the scene (e.g. [tense music])
• Language tagging when the dialogue switches languages within the same scene
• Specific formatting conventions (color or screen position) when there are several speakers at once

Why judgment matters more than the template

Not every sound needs to be subtitled: doing so without judgment produces a screen so cluttered it's about as inaccessible as having no subtitles at all. The real work of good SDH subtitling is deciding which sound carries information the viewer needs to follow the plot and which is simply ambient, and communicating the former without burying it under the latter.