voice interface
8 Aug 2019 13 min to read

Voice Interface Design – How to create the invisible interface

Great design is achieved not when there’s nothing left to add, but when there’s nothing left to take away – said Antoine de Saint-Exupéry. And it’s not only about the design you can SEE, but also the design you can only HEAR. Let’s take a look at how great the voice user experience design should be done.

In this article, you can find some great tricks and tips on how to design great voice interface. Sounds scary? After the read, you’ll get your courage back!

  • few words about research and creating personas and why it’s so crucial
  • creating a scenario – possible ways and solutions
  • meeting your audience and testing your design among people 
  • after-work conclusions on how your product is performing

Human to human communication is said to be very complicated. There are a lot of languages, dialects, spelling differences, intonations, and of course – interpretations, so sometimes we have to concentrate very hard to understand what someone else is saying, and the thing that allows us to do so is our intelligence combined with intuition.

But in the 21st century, we communicate not only with other people but also with electronic devices. Artificial intelligence and machine learning are on a very advanced level these days, but there’s still a lack of intuition here, so voice experience designers have a tough nut to crack when creating a user-friendly journey for IoT (Internet Of Things) devices.

voice interface google home

The Google Home smart speaker user base expanded by 7.2 million in the U.S. in 2018 according to data compiled as part of the 2019 U.S. Smart Speaker Consumer Adoption Report. That reflects a rise of 600,000 more new Google Home users than Amazon Echo added in 2018.

The invisible experience

According to my observation, many people think that designing voice experiences is a completely different thing than creating graphical user interfaces. If you’re among them, you’re wrong! Designing voice-based experiences is said to be a new direction of UX design, but it’s definitely not – it’s just a next step that happens naturally. Even more – it’s a great idea to adapt the visual design experience process (eg. 10 Usability Heuristics for User Interface Design from 1994) for creating voice-based devices.

Here are some precious tips for creating a winning voice user interface – let me know if they helped you!

1. Do your homework. RESEARCH.

Similar to every digital product, you need to apply user-first design when creating a voice-based experience. That’s why user research is CRUCIAL here. Its goal is to understand the needs and behaviors of the target user, and gathered information will be the product’s foundation. In order to develop your personas, you should ask yourself who would use this app and how would it help to solve their problems in the quickest and most effective way.

After establishing some perfectly-crafted personas, you need to focus on:

  • Investigating the current experience and ways that users are solving the problem now
  • Identifying pain points and finding spots to improve the user experience
  • Researching the user language by finding the EXACT phrases that people use when they speak with other people. Knowing the specific lingo will definitely help you to design a process for different utterances of the specific target group

In order to get a full understanding of voice-based systems, you can also buy or borrow a smart speaker and test it like there’s no tomorrow. It’s always a great idea to try some different voice apps and check how other voice interface designers approached the problem. Find the best examples and analyze them step by step, writing down every inspiring solution – you never know when you’ll need some quick inspiration.

2. So whaa-so whaa-so whaa, so what’s the SCENARIO?

When A Tribe Called Quest asks, you answer
with a winning scenario of a voice-based experience.

In this step you have to shape the future product and define all of its capabilities.

Now your main goal is designing scenarios that will have the highest value for your target users. First of all, you need to figure out which of 4 possible voice input triggers will be relevant in your case.

The voice input triggers:

  • Voice trigger – the user speaks a phrase that prompts the device to begin processing the speech
  • Tactile trigger – the user presses a physical or digital button
  • Motion trigger – the user waves his hand in front of a sensor
  • Device self-trigger – an event (like a car accident) or pre-determined setting turns the device on

When kicking off projects involving visual interfaces, the first step for most designers is a whiteboard to sketch out some raw concepts of the user experience. But what if your product doesn’t have a screen? Just create simple scenarios, by writing down a basic back and forth conversation between the user and the voice app.

Don’t forget to answer additional questions, eg. Will users know what they want to do or should you offer some options? What users will say to start the app? What the tone and personality of the voice experience will sound like? And if you feel you’re stuck just ask yourself – how would you design if it was a visual user interface? Then try to translate it into voice.

After designing the scenarios, you have to make sure they perfectly work with voice.

Remember that the ultimate goal of the project is providing users the ability to solve the problem way faster than using any alternative experiences. Keep the scenarios short, because selecting from a long menu is very difficult with voice interactions.

Remember: 3 selections maximum. If you have more than 3, most probably you should reframe the scenario.

Btw. don’t forget to prepare the error scenarios! It’s very likely that users will speak too fast, too slow, too quiet, etc., etc., and you have to be prepared. Make sure your scenario involves a request for repeating the voice command, eg. Say it again?

Another thing is the possibility that some users will get confused and could use some navigation through the experience. For example:

Voice-based device: What’s your date of birth?

User: Ummm…

Voce-based device: Jason, please tell me your date of birth using 2 digits for the month, 2 digits for the day, and 2 for the year

3. Time for some roleplaying!

It’s time to face the public.

Yes, now!

No, it’s not too soon. You have to test the experience before creating it, and even building the prototype. It only takes a group of people that match your target users and a person playing the artificial intelligence experience that you designed. Check every possible iteration with your people and write down every moment of hesitation, lack of desired option, etc. After this interview your users and ask them to rate the experience.

Now you have all the knowledge to do some changes.

4. Make yourself a cup of tea. RESTING PHASE.

Now it’s time to let the other team members do some work. Time to build this freakin’ device from scratch and give it to the people!

Now your role is to keep your finger on a pulse and test because some issues like to get out of their caves at the final stage – you know how it is!

5. Now let the voice app speak for itself (LOL).

After rolling out your app, you need to start tracking its performance among the target group.

Some key metrics to keep your eye on every day:

  • Intents and utterances
  • User engagement metrics
  • Behavior flows

Tracking these metrics regularly will help you to provide an excellent voice-based experience since you’ll be able to catch the source of the problem and redesign the process in a quick and effective way.

Wrapping up!

Voice assistants are quickly becoming a common part of our daily lives – according to a survey run by Adobe, 76 percent of smart speaker owners increased their usage of voice-enabled devices over the last year. It should be crucial for designers to create voice-based experiences that are based more on human2human than human2machine communication style, by knowing who and why they design for.

Happy designing!


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