To create an inclusive voice experience, your skill should be designed in a way so that it is available and delightful for every customer who wants to use it. To do this well, the skill must be designed with accessibility in mind so it can be used and accessed by the widest range of people with varying abilities.
Here are a few accessibility principles and recommended best practices to follow when designing Alexa skills for everyone.
Creating Accessible Voice-Only Experiences
Even though there are Alexa-enabled devices with screens available to customers, all skills should remain voice-first, using visuals mainly to complement and supplement the voice UI, and not replace it. This means your skill should allow your customers to use only voice commands to navigate through your experience, or to discover what's displayed on screen.
Some customers may use screen readers on devices like the Echo Show or Echo Spot, and the voice response should provide an appropriate hierarchy of information for the screen reader to identify the importance. Consider delivering less information with fewer options to help customers navigate and understand their next selection. Your prompts should be short enough to be read aloud by a person in one to two breaths. For example, if you want to communicate a list of information to the customer, have Alexa respond with only a few items in a list, rather than responding with every possible item in the list.
Use pauses and transitions in your skill dialog to ensure customers with listening or speech limitations are able to engage. For example, if offering a customer more than one option in a response, a best practice is to clearly indicate the end of one option and the beginning of the next using natural breaths and pauses. If changing subjects, consider using transitional phrases such as “Next” and “Now let's talk about …” to help the customer clearly understand that Alexa has moved on to the next thing.
Additional ways to assist customers with your voice experience is to handle unexpected utterances gracefully, and consider writing re-prompts to add clarification on the type of information the skill is trying to collect. If Alexa doesn't hear or understand a response from a customer, it can request the information once more providing the customer with a chance to try and fix the utterance before context is lost. This is why it's also very important to support the AMAZON.RepeatIntent so that customers can ask your skill to repeat itself at almost any time, whether they're using the skill in a noisy common area or they're having trouble understanding the meaning of the dialog.
Creating Accessible Voice-First, Visual Experiences
When it comes to designing inclusive visual responses for your skill, the most important things you can do is to make sure your skill meets the AA accessible standard contrast ratio of 4.5:1 for all text and colors. This is particularly important if you are going to be layering foreground text over background images, and will ensure that your text content is legible and identifiable if a customer is looking at the device. We recommend applying a minimum overlay color of 60% black to background images in order to avoid contrast issues. You can do this by setting the scrim parameter to be darker. You can verify your color combinations through a variety of online tools to check if you've got it right before developing.
Because customers may not always be near a device, use the APL type ramp to scale your text content appropriately across devices, ensuring that it is legible at given distances. This may mean that the font size you select is larger than what you may be accustomed to, but it will ensure that if a customer is far from their device they still can quickly read the content being shown on the screen. Also consider pairing light and bold weight fonts to create additional contrast and a glanceable hierarchy. You can learn more about typography for your skill here.
Your skill should also limit flashing, making sure that elements do not flicker, flash, or blink unless absolutely necessary for your experience. If you do need to draw attention in this manner, ensure that the frequency is greater than 2 flashes per second. This will help customers who may experience a seizure when exposed to certain visual images like flashing lights or patterns.
Now that you know a little bit about what it takes to create an accessible skill for Alexa, we encourage you to apply these principles to your work moving forward. Your customers will thank you for it.
Enter the Alexa Skills Challenge: Multimodal
In addition to building a visually rich Alexa skill with APL, you can enter the Alexa Skills Challenge: Multimodal with Devpost and compete for cash prizes and Amazon devices. We invite you to participate and build voice-first multimodal experiences that customers can enjoy across tens of millions of Alexa devices with screens. Learn more, start building APL skills, and enter the challenge by January 22.
More Resources to Get Started with APL
- Alexa Design Guide
- Steven Arkonovich Enhances Voice-First Alexa Skills with Visuals and Touch Using the Alexa Presentation Language
- How to Design Visual Components for Voice-First Alexa Skills
- 10 Tips for Designing Alexa Skills with Visual Responses
- 4 Tips for Designing Voice-First Alexa Skills for Different Alexa-Enabled Devices
Source: Alexa Developer Blog