Essential Guidelines to Follow When Designing a Voice User Interface

It’s all about our voices today; what they can do and what we can do with them. As consumers, we like the idea of being ‘hands-free.’ We like doing whatever we want and getting whatever information we need without having to lift a single finger. Thankfully, voice user interfaces (VUIs) are there to help us out.

At their most basic level, VUIs allow humans to interact with computers through voice or speech commands. Whether real or fictional, they’re behind your favorite voice experiences like the Star Trek computer, Tony Stark’s J.A.R.V.I.S., Amazon Alexa, Apple’s Siri, Google Assistant, and many other voice-enabled devices.

Today, from eCommerce web development to vacuum cleaners, VUI-backed technology is practically everywhere. In fact, it’s gotten to the point that a prerequisite for tech devices to be successful is for them to have some sort of voice-command feature that allows for hands-free control. How did we get here, though?

The Growth of Our Voice

First we clicked, then we gestured, and now we’re commanding; human-computer interactions are quickly become commonplace. So much so that voice technology’s rapid growth in popularity can be attributed to a mixture of changing trends and technological advances. On the trends side, our love for smartphones has been steadily growing in the past decade to the point that we have been utterly unable to put them down. They’re our go-to browsing option, and with them come voice assistants like Siri that do everything from setting alarms and sending messages, to telling jokes.

Fun Fact: Siri, Apple’s AI assistant for iOS and HomePod devices, is helping more than 40 million users per month!

On the technological side, breakthroughs in AI have spurred more and more companies to dip their toes in the voice technology waters. As a matter of fact, all ‘Big Five’ tech companies — Amazon, Apple, Facebook, Google and Microsoft — have either designed or are currently designing voice user interfaces for their voice-enabled AI assistants. Narrowing on the Amazon, they describe rel="noopener noreferrer" four broad trends fueling the rise of voice:

• Web Services, IoT Have Opened Doors: Web services and the Internet of Things provide ready-made opportunities for voice. Sensors and readouts, for example, make for natural smart-home integrations.
• The Science Is Accessible: Now anyone can leverage learnings from fields like automatic speech recognition (ASR), natural language understanding (NLU) and text to speech (TTS).
• The Hardware Can Support the Use Case: Existing hardware can support far-field voice input processing (FFVIP), enabling a wider range of experiences with VUIs.
• AI Is Making VUIs Smarter: Thanks to advances in machine learning, VUIs are learning and adapting to users’ speech patterns, preferences, and contexts over time.

With these trends backing them up, VUIs are continually improving. They’re learning our speech patterns, they’re building their own vocabularies, and with each interaction,     they’re getting smarter by the day.

The Uses of Our Voice

As smart as they are, VUIs and voice assistants are opening the door to a life of leisure characterised by voice-enabled commands. Whether it’s a smart speaker or a smartphone, voice-based products are acting as personal assistants that can answer practically any question we ask of them — and if they can’t, they’re more than willing to point us toward the right direction with a quick Google or Bing search.

Apart from queries, these devices can also take care of practically anything in an instant. Do you want them to tell you what’s in your calendar this afternoon? No problem. Do you need them to book a cab to Piccadilly Circus? Of course. Would you like to hear a specific song, artist or genre? You got it.

Basic Principles for Designing Voice User Interfaces

That’s what a combination of VUIs and good voice interaction UX enables. In other words, what you should strive for if you’re designing a VUI. The problem with creating a seamless design is that many designers and developers equate mobile and desktop interfaces with their voice counterpart — a mistake that leads to confusion and poor outcomes. They don’t realise that voice should be treated as its own thing; that voice interfaces are a whole other story.

With that in mind, there are a couple of basic principles for designing voice user interfaces that should always be followed. For example and as we just covered above:

Consider VUIs as Their Own Thing

You simply can’t apply the same design principles used for graphical user interfaces (GUIs) as voice user interfaces. For example, whereas GUIs are all about visuals, VUIs are all about voice. That is to say that with VUIs, users have no indication of what they can or can’t do right off the bat. As a designer, you have to clearly state what interactions are allowed and what functionalities are available.

Understand Your Users

For a design — any design — to be successful, there must be an intimate understanding of the end-user, and VUIs are no exception. It boils down to the fact that you have to know how and why your users are going to interact with your VUI if you plan on designing one that they’ll actually want to use.

Give It Personality

Consumers don’t like or want boring. They’re attracted to personality, and this attraction translates to VUIs as well. Part of the glamour that comes with using voice assistants is that you can, to a certain extent, imagine you’re talking with a real person, and this is all due to the personality that VUI designers bestow on their creations.

Provide Feedback

As humans, we always need feedback, otherwise we have no way of knowing how things stand. For example, imaging asking a voice assistant to turn off the lights you accidentally left on when you left your flat. Without feedback, you have no way of knowing whether or not your command was carried out, and you may be inclined to go back to reassure yourself; an act that completely negates the benefits of voice assistants.

Along the same lines, users also need immediate feedback when they’re talking to the VUI-enabled device so they know with certainty that what they’re being heard. For example, Siri has a wave visualisation wiggle and Alexa has a light that illuminates when users start to speak.

Final Thoughts

To design a good voice-enabled device, you need a good voice user interface backing it up. You need to think like a digital creative agency and acquire an intimate understanding of your end users so you know what they want; you need to provide feedback so they know your VUI knows what they want; you need to give it personality because people don’t like boring; and most importantly, you need to consider VUIs as their own thing.