Voice AI wake word
Feb 01, 2022
7 MIN READ

5 Important Keys to a Truly Hands-Free Voice Assistant

As voice technology continues to improve, costs decline, and more connectivity options become available, more brands are considering adding voice user interfaces to their products and services. Other factors such as privacy concerns, the need to maintain customer relationships, and the desire to remain competitive in the market are fueling a rising trend for companies to invest in their own voice assistants and deliver customized voice experiences to their customers. 

The rapid adoption of voice assistants among the general population is actually creating demand for more convenient, easier, and more hygienic ways to interact with the world around us. However, the real convenience of hands-free, always-on voice interfaces is largely dependent on how users begin the conversation. If the device has to be within reach and pushing a button is required to wake up the voice assistant, users might as well continue with typing and swiping. 

For a truly hands-free assistant, you need a wake word. When you create a wake word, there are 5 things you should follow to make sure you do it right.

1. Make your wake phrase audibly different 

Your wake word needs to have some differentiation. It shouldn’t sound too similar to other words or phrases in your chosen language. 

For example, If your company is called “Bello”, and you’d like your wake word to be “bello”, that’s too similar to “hello”. 

According to Darin Clark, Director BD at SoundHound, “When you create a wake phrase, you’re essentially waking up that device and you’re speaking to command that device to do something. So, you really want it to have a good understanding when you’re speaking to it versus speaking to somebody else in the room or speaking about it or anything along those lines.”

“When you create a wake phrase, you’re essentially waking up that device and you’re speaking to command that device to do something.”

Darin Clark
Director of Business Development, SoundHound

If your wake word isn’t unique, then there’s a greater chance of your assistant ‘waking up’ when it’s not intended to be invoked. This is known as false acceptance. The opposite effect, a false positive, happens when your voice assistant is unresponsive to your wake word.

2. Make sure your wake word is not too long

There isn’t a specific, maximum limit for the length of a wake word, technically. However, if your wake word is too long, you risk some pretty severe user experience limitations. 

People don’t have great short-term memories. If your wake word is too long, then there’s a good chance that people won’t remember it. Either that, or it takes a heavy cognitive effort to remember your wake word. Both of which aren’t great user experiences. 

The optimum length for a wake word is between four to five syllables.

The optimum length for a wake word is between four to five syllables. It’s typically best practice to have at least three syllables to give the voice assistant enough of a pattern to recognize accurately.

Insider knowledge: This is why the Google Assistant wake word is “Hey Google” or “OK Google”: it’s three syllables.

3. Don’t have too many similar sounds 

Your wake word should have some variation in the sounds it contains within it and shouldn’t have too many similar sounds. For example, if Santa created a voice assistant, then a wake word of “Ho, ho, ho” contains too many concurrent “ho” sounds for it to be an effective wake word. “Hey Santa” would work much better.

“You really want some phonetic variation in the phrase and lots of differentiation between consonants and vowels in order to really create a different sound than other words or phrases in the language. You don’t want a lot of the same sounds repeated,” according to Darin.

You really want some phonetic variation in the phrase and lots of differentiation between consonants and vowels in order to really create a different sound than other words or phrases in the language. You don’t want a lot of the same sounds repeated.”

Darin Clark
Director of Business Development, SoundHound

There’s a way we can actually look at specific wake phrases and determine if it doesn’t have enough phonetic variation, if it has a lot of phonetic variation, and if it’s too similar to other phrases that are pretty common in the language. We can then make a recommendation for usage based on all these findings,” he said.

4. Make your wake word easy to differentiate

To eliminate accidental wake-ups—or instances where the voice assistant is not responsive to user queries—it’s important to differentiate your wake word from common words, names, and even the name of your company.

There are a number of ways to ensure your wake word doesn’t suffer from a lot of false acceptances or false rejections and to differentiate it from normal conversation. 

To eliminate accidental wake-ups—or instances where the voice assistant is not responsive to user queries—it’s important to differentiate your wake word from common words, names, and even the name of your company.

Here are the top 3 ways to differentiate your wake phrase:

1. Differentiating between the device

Your wake word should be different from the name of the device that it runs on. For example, having the wake word “Echo” runs the risk of the assistant being activated when someone is discussing the device in normal conversation. Although Amazon allows you to set its wake word to “Echo”, those that do will notice the device wake-up when your friend asks “Do you have an Echo?”

2. Differentiating between the company

If your company name is Delany and your wake word is “Delany”, then you’re again going to generate a lot of false acceptances. Your assistant will wake up when it’s not intended to be invoked more often.

This is why brands like Pandora and Hyundai add words like “Hey”, “OK”, or “Hello” before their brand names in their wake phrases. “Hey Pandora” is enough to differentiate the wake word from somebody just talking about the music streaming service during a normal conversation.

3. Differentiating between natural conversation

We’ve all had the experience of having our Echo devices wake up during the course of a natural conversation. It must be a nightmare having an Echo if your actual name is Alexa. 

If you decide you want to give your product a name, instead of having your users use the company or product name, you’ll need to think through all the connotations that name may have for people. In addition, if the name is too common, it may spark those false positives you’re trying to avoid. Choose a gender-neutral name that is not shared by real people and ideally one that’s an extension of your brand.

A good wake word includes a combination of sounds that are pleasing, but not easily rhymed and easily distinguishable from language or sounds made during the course of a natural conversation. 

4. Make your wake word work across borders

Many companies have customers and users across borders, and if you don’t have international customers today, maybe you will tomorrow. Even if your customers are all located in North America, their native language may not be English. In addition to speaking an array of languages, people in various geographical areas may speak the same language with a variety of accents.

In addition to speaking an array of languages, people in various geographical areas may speak the same language with a variety of accents.

Different languages have different phonetic make-ups. If you listen to a native Mandarin speaker and compare the sounds produced when speaking Mandarin to the sounds produced by someone whose native language is German, you’ll notice a number of differences. The frequencies produced, the tonal variations and even the muscles used to produce the sounds of different languages vary greatly. 

So, when designing your wake word, try to make sure that you create something that’s phonetically easy to say, no matter the base language your user speaks. 

The growing trends toward truly hands-free voice experiences

Voice assistants coupled with wake word technology can provide value for any device you can imagine, from airlines to conference halls, elevators, mobile apps, cars, train ticket machines, ordering kiosks, and everything in between. The appeal of hands-free voice interactions is creating a need for a consistent voice across channels that includes the same voice assistant and branded wake word.

“We are seeing more companies acknowledge and recognize the value of a custom branded voice assistant for their app or their device. They want a custom wake word that’s going to reinforce their brand and promote brand loyalty. Soon, it’s going to be critical to have a customized voice assistant and wake word that invokes that voice assistant across all channels and devices,” Darin said.

If you haven’t already started thinking about how and where you will create your unique voice experience, a branded wake word may be a good place to start.

VUX World’s renowned industry experts offer unbiased, objective, and agnostic conversational AI consulting. We help you explore the value of conversational AI technologies, define the future of AI-powered customer experience for your business, and put together a plan to get you there.

Kane Simms is the founder of VUX World. Join him for a dog walk on LinkedIn, where he shares insights on the voice and NLP space while walking Winston, the sound hound. Tune into the VUX World Live podcast for interviews with the world’s leading minds in conversational AI or join the CAI and NLP newsletter.

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