Live captions for deaf and hard-of-hearing audiences

Who do live captions help?

They let people follow a talk as it happens by reading what the speaker says, without relying on hearing, a hearing aid or lip reading.

• Deaf and hard-of-hearing people who read the speaker’s language, especially those who lost their hearing later in life and never learned a sign language.
• The whole audience: at the back of a large room, in a noisy venue, with an unfamiliar accent or a technical term, reading what is said helps everyone.

Captions can stay in the speaker’s language, or a session can show a translation into one of seven languages, but only one language at a time. Same-language captions have been tested from French to French; for another language, English included, ask us for a trial first. To offer captions and a translation together, you need two sessions running side by side, subject to our availability.

What do captions not replace?

• Sign language. ASL, LSQ and other sign languages are full languages. The Accessible Canada Act recognizes American Sign Language, Quebec Sign Language and Indigenous sign languages as the primary languages for communication by deaf persons in Canada (subsection 5.1(2)). For someone whose first language is a sign language, an interpreter is still needed.
• CART and human captioning, when every word matters. A professional captioner transcribes the speech, identifies speakers and meaningful sounds, and corrects on the fly. For an exam, a hearing, a medical appointment or a negotiation, that is the standard.

The right setup is chosen with the people who need it. Waavoo can run alongside an interpreter in the same room, for those who read rather than sign, or be enough on its own when automatic captions meet the need.

How are the captions read?

• On a phone, through a link or QR code, with no app and no account. Each reader picks one of five themes, including a high-contrast theme, and a text size from 24 to 150 px (28 px by default on phones). Line spacing is adjustable too.
• On the room screen, in projection mode: large captions with no interface at all. The session’s QR code can be brought back with one key for latecomers.
• As the words are spoken: the sentence in progress may still be corrected while it is being written, then it settles.

By default, words still being recognized and earlier lines are dimmed, to guide the eye to what is being said. The “Dim earlier lines” setting shows all text at full opacity.

What does the viewer guarantee under WCAG?

The W3C’s Web Content Accessibility Guidelines (WCAG) are the international reference for digital accessibility, and the basis of rules such as the ADA Title II web rule and Section 508 in the United States. The viewer, the page where the audience reads the captions, is built to the WCAG 2.1 success criteria that apply to it, up to level AAA:

• Contrast (1.4.6, AAA). At least 8.3:1 on each of the five themes. Dimmed text keeps 4.5:1, the threshold for large-scale text, except at the top of the area, where lines fade out as they leave; the “Dim earlier lines” setting removes both the dimming and that fade.
• Text size (1.4.4). From 24 to 150 px, and browser zoom is never blocked.
• Visual presentation (1.4.8, AAA). Any text colour, a background from five light or dark themes, adjustable line spacing, never justified text.
• Small screens (1.4.10). No horizontal scrolling down to 320 px wide.
• No flashing (2.3.2, AAA). Nothing flashes more than three times per second, and text and indicator animations stop when the device asks for reduced motion.
• Screen readers. Captions sit in an “aria-live” region, updated as speech comes in. Announcements have not yet been checked with a real screen reader (NVDA, VoiceOver).

Our accessibility statement details each criterion and how it is checked, on every code change. It covers the display, not the accuracy of the captions, which depends on automatic transcription (see the limits).

How do you plan a captioned event?

• Ask about needs at registration: sign language interpreter, captions, hearing loop. Each person knows what works for them.
• Put everything through a microphone. Whatever does not reach a microphone is not captioned: plan a microphone for audience questions.
• Mention captions in the invitation. The link and QR code only exist once the session is opened, shortly before the event: show them then at the entrance and on the room screen.
• Keep seats facing the screen if captions are projected, without blocking the view of an interpreter.

Audio setup and network requirements are covered on our live translation for conferences page. For lectures, see also live captions for universities.

What do the rules say?

In the United States, the regulations implementing the Americans with Disabilities Act require public entities, such as cities or public universities, and public accommodations, such as conference venues or private colleges, to furnish appropriate auxiliary aids and services where necessary for effective communication (28 CFR 35.160 and 28 CFR 36.303). Qualified interpreters, real-time captioning and real-time computer-aided transcription are among the examples they list; the Department of Justice describes real-time captioning (CART) as a service in which a transcriber types what is said.

The right aid depends on how the person communicates and on the nature, length, complexity and context of the communication. Under Title II, the person’s request gets primary consideration. Under Title III, a business should consult the person whenever possible, and the final decision is its own, provided the method chosen results in effective communication.

In Canada, the Accessible Canada Act aims for a Canada without barriers on or before January 1, 2040, including in communication (section 5). It applies to federal entities and to businesses within the legislative authority of Parliament (section 7). In Québec, section 10 of the Charter of human rights and freedoms guarantees the full and equal exercise of human rights and freedoms, without discrimination based on a handicap or the use of any means to palliate it.

These rules list kinds of aids and services; none names a vendor. Whether a given setup provides effective communication depends on the person and the setting: Waavoo can be part of the answer; it does not replace that assessment.

What are the limits?

• Accuracy. Proper names and rare terms can be misrecognized. We do not publish an accuracy figure yet; the safest test is a sample of your own event.
• No speaker names, no sounds. WCAG defines captions as covering the non-speech audio needed to understand the content too. Waavoo transcribes speech only: it does not show who is speaking, nor laughter, applause or music.
• A delay. The text follows the speech with a lag: in a question-and-answer exchange, leave time to read before handing over the microphone.
• Anything off-microphone is not captioned.
• The network. Captions depend on the venue’s connection and on our servers: for someone who relies on them, plan a fallback.
• One language at a time: captions or a translation, not both at once in the same session.
• No text after the event: that is the price of “no text is kept”.

Frequently asked questions