Introduction
Patient education videos must be clear, accessible and culturally sensitive. Voice-over and subtitles are complementary: audio supports comprehension, while captions reinforce the message for viewers who need visual aid. This guide presents concrete practices for low-literacy audiences, timing recommendations, and a robust multilingual subtitling workflow.
1. Core accessibility principles for health videos
- Use plain language, short sentences and direct verbs.
- Prioritize critical information: what to do, when, and who to contact.
- Combine audio, captions and visual cues (icons, numbered steps) to reinforce understanding.
- Validate all content with clinical staff and representative users.
2. Voice-over: clarity and empathy
- Voice & tone: choose speakers with clear diction and a calm, measured pace.
- Adaptation over literal translation: localize expressions and examples rather than translating word-for-word.
- Pause length: include pauses after key instructions to allow processing.
- Consistent voice identity: use consistent voice talent across campaign materials to build familiarity.
- Technical quality: record in controlled environments; avoid background noise and reverberation.
3. Subtitles for low-literacy audiences
- Plain language: keep captions short (max 1–2 lines on screen) and use common words.
- Reading speed: display each caption block for at least 3–4 seconds (adjust by length).
- Line length: aim for under 40 characters per line for easy mobile reading.
- Font & contrast: legible size (min 16–18 px on mobile), sans-serif font and high contrast.
- Placement: avoid covering important visuals; place captions in a fixed safe area.
- Audio synchronization: show captions slightly before or with the spoken phrase to support audio-text mapping.
- Avoid jargon: replace technical terms or provide short visual glossaries.
4. Multilingual subtitling workflow (practical)
- Master script validated: source script approved by clinicians.
- Localization: translators adapt content for local context.
- Timing (cueing): subtitler times captions to the audio track.
- Linguistic review: native reviewer checks readability and fluency.
- Clinical review: health expert validates medical accuracy.
- Quality assurance: automated checks (length, invalid characters) plus human QC.
- Deliverables: .srt/.vtt files, video with burned-in captions, and dubbed audio files if required.
- User testing: test with target audiences to measure comprehension and reading times.
5. Special considerations for low-literacy audiences
- Add pictograms or images that illustrate actions alongside captions.
- Offer voice-first versions plus large-caption versions for readers.
- Provide downloadable plain-language transcripts.
- Break content into short micro-learning modules.
6. QA and accessibility compliance
- Follow web accessibility guidelines (e.g., WCAG) for captions and transcripts.
- Document approvals: final script, subtitle versions, reviewers and user-test outcomes.
- Test playback on mobile and low-bandwidth conditions.
7. KPIs and recommended metrics
- Comprehension rate per module (pre/post question sets).
- Video completion rate.
- Average reading time per caption (indicator of timing adequacy).
- QA incidents per 1,000 captions (sync or technical errors).
- Qualitative feedback from low-literacy users.
Quick checklist (implementation)
- ✅ Clinically validated plain-language script.
- ✅ Voice-over by trained speaker with appropriate tone.
- ✅ Short, synchronized captions (min 3–4 s per block).
- ✅ Deliverables: .srt/.vtt + video with captions + dubbed tracks as needed.
- ✅ Linguistic + clinical reviews completed.
- ✅ User comprehension testing performed.
- ✅ Plain-language transcript available.
Conclusion
Effective voice-over and subtitling turn a video into a trusted patient education tool. At SumaLatam we design multilingual subtitling workflows, produce accessible voice-over and run user tests with real patients. Contact us to pilot an accessible video for your program.
