Designing and building voice-first user interfaces are fraught with challenges— we recommend multi-modal interfaces with clear requirements.

Getting Voice-First User Interface Design Right

June 8, 2017

Designing a Voice Interface

As voice user interfaces (VUIs) have become a part of people’s homes and lives businesses have two imperatives:

  • Onboard users effectively so they know what the device can do and how they can do it
  • Design the interface in a way that feels natural to use

If companies want customers to use voice-first devices for tasks more complex than the basics (setting timers, playing music, and making lists) then voice-first apps must seamlessly combine components of natural conversation and audio/ visual feedback. For example, when a user is wanting to fulfill a goal - listen to music, pay a bill, learn the forecast- they command the device. They say something like, “Hey Siri, what’s the weather like?”

At this point, there are a few questions the user has. For starters, how does the user know Siri heard? How does the user know Siri is thinking/ searching/ calculating? How does the user know that Siri will respond? Or even how does the user know that Siri is plugged in and turned on? When people interact with voice-first devices, they are engaging the device first with their voice. Promptly after, the device provides signifiers to inform the user of its status and activity. How companies navigate composing these interactions requires understanding the user, the user’s goal, and how they will first attempt to interact with the device.

For companies seeking to pursue a voice-first interface here are a few design/build process considerations:

  1. Is it possible to fulfill your user’s goal with a voice interface? Voice-first UIs are effective when the queries are simple, easy to conduct, and respond to using voice.
  2. Consider prototyping the conversation. Does the conversation flow well? What kinds of prompts should the device be required to recognize from users? The conversation should feel natural.
  3. Testing with real users provides valuable insight for designing an effective voice-first interface.  By user-testing, valuable information will be revealed about how users will speak and what prompts you need to plan for. User testing will also reveal unanticipated requirements that will be needed to support in order to create a seamless user interaction.
  4. Iterate your design! The best designs are those where insight revealed during user testing impacts future interface versions, etc.

Not only is the iterative process above an effective approach for designing a voice interface, but the best practices below are widely accepted standards for increasing one’s chances of success after launch.

Voice-First User Interface Design Best Practices

Provide sufficient onboarding.

As tasks become more complex, the absence of a traditional UI can decrease a product’s usability. It is critical for sufficient guides to be provided upon start-up. These help users understand what the product can do and how it fits into their life.

Design it like a real conversation.

Many cite Paul Grice’s Cooperative Conversation maxims as good principles to follow. Essentially, his principles focus on the quantity of information (not too much and not too little), quality (being genuine), relation (being relevant to the task at hand), and manner (be clear, concise, unambiguous, and not obscure).

Account for variations in user commands and responses.

Consider whether to allow users to prompt and respond freely or to provide multiple-choice options. Whichever route is opted for depends on the goal of the user. In some cases, listing options is necessary. Know that this can detract from the natural feel of the conversation.

Provide the user with signifiers and feedback when needed.

Users expect prompt feedback so they know what the device is doing and if they have been heard. For example, consider the task of changing the volume. If a user wants to turn the volume down, they ask the device to turn down and they expect to hear that the task has been completed. By providing feedback to the user, the user is assured they have achieved their goal.


Designing an invisible user interface might seem daunting, but by considering one’s users and through a goal-directed design process, launching a new product can be successful and innovative. Through considering one’s user, how they might interact with the device, conducting user tests, iterating on one’s design, and adhering to these best practices, decision-makers can act strategically, make informed decisions, and launch solutions that are adopted into people’s lives.