We live in an era of speech interaction via services like Cortana. Adaptive cards are designed from day one to support speech, enabling cool new hands-full scenarios.
speak tag enables the adaptive card to be delivered to an environment where a visual display is not primary experience, such as to a car dashboard while driving.
To support speech we have a speak property which contains text to say to the user. The text can be annotated using speech synthesis markup language (SSML). SSML controls the speed, tone, and inflection of the speech. It even allows you to stream audio or a render a TTS audio stream from your own service, giving you a great deal of flexibility for customization.
There are two patterns for speak property usage by a host application:
- On delivery - When a card is delivered, the client may opt to read the Speak property for the card to describe the card as a whole.
- On demand - In order to support a richer accessibility model, the schema supports a speak tag for each element. The client may read a Speak property for each element in the card.
"speak":"hello world!" "speak":"<s>This is sentence 1.</s><s>This is sentence two</s>" "speak":"<speak><audio src='https://www.soundjay.com/misc/bell-ringing-04.mp3'/><s>Time to wake up!</s></speak>"
Speech content design
Content designed for speech is different from content designed for visual display. When you design a card, you are designing an entire visual experience to present information to a user in a way that delights them. When designing for speech, you should think about how to verbally describe the content in a way that delights the user.