SDH — subtitles for the deaf and hard of hearing — go beyond dialogue. They identify speakers, describe meaningful sounds ([alarm sounds], [music swells]), and mark tone where it carries meaning. Regular subtitles assume the viewer can hear; SDH assumes they cannot.
The distinction is practical and legal. Accessibility regulation — the ADA and Section 508 in the US, the European Accessibility Act, and broadcast codes worldwide — increasingly mandates SDH for published video. For training and product video, SDH is also simply good design: many viewers watch muted on factory floors, in open offices, and on social feeds.
Producing SDH in multiple languages adds a localization wrinkle: conventions differ by market. German SDH uses different speaker-label conventions than English; Arabic SDH must handle right-to-left positioning so labels never collide with on-screen text. Sound descriptions must be translated, not transliterated — [telefon klingelt], not [phone rings].
MediaLocalize produces SDH and standard subtitles in 20+ languages, timed to reading-speed standards and delivered in SRT, VTT, SCC, STL, or broadcast formats — with burn-in versions when you need them.