Voice interfaces are the future
Voice interfaces suck

Agenda
1. What are voice interfaces?
2. When they suck
3. When they’re great
4. How to design for them
5. What the future holds

Voice user interfaces (VUI) enable
users to interact with computers
through voice and speech.

Speech recognition
Speech synthesis

Source:Nandini Stocker @ Google

• We are born knowing the
fundamental rulesfor
language(LAD)
• Young childrenwill notice if
adults around them made
grammatical mistakes.
Noam Chomsky

• Context
• Experience
• Empathy
• Subtext
• Common sense
Human to human conversations

Are we there yet?

NOPE

But we’ve gone a long way

The Voder-1930

The Voder - 1930 The Harpy
System - 1976
Hidden Markov
model – 1980s
Dragon Dictation
– 1990s Google voice
search - 2008
Siri - 2011Audrey - 1952
Alexa - 2014

Technological constraints
Medium constraints
(temporary)
(permanent)

Conversational systems are not
really “smart” yet
Technological constraint #1

Speech recognition is still not
100% accurate
Technological constraint #2

Speech output still
sounds robotic
Technological constraint #3

Voice is a
transient and invisible medium

Reliance on recall
• Remember how to ask things
• Remember what you’re allowed to ask
• Remember what you said throughoutthe
entire exchange
Medium constraint #1

Source:Nate Clinton @ Cooper

Linear progress
• You can’t skim throughinformation
• You don’t see the entire picture
Medium constraint #2

Medium constraint #3
Poor error prevention
& recovery
• Since voice is invisible, you can’t
always spot errorsstraightaway
• Once you spot an errorit’s not easy
to correctit

I want to go on a trip

Ok, where would you like to go?

Auckland

I want to go on a tripOk, where would you like to go?Auckland
Your next destination Oakland, California.
From which airport would you like to depart?

I want to go on a tripOk, where would you like to go?I actually meant Auckland, New Zealand

I want to go on a tripOk, where would you like to go?Auckland
Your next destination Oakland, California.
From which airport would you like to depart?
I actually meant Auckland, New ZealandGreat! A flight from Oakland Califorina, to
Auckland, New Zealand!

People can’t listen as
quickly as they read
Medium constraint #5
Listening rate: 175-225 words per minute
Reading rate: 350-500 words per minute

Privacy
Medium constraint #6
Thereare things you won’t want to speak about in
front of others.

Are they always bad?

Context
Aarron Walter’s hierarchyof user needs

Speed
• Search
• Call an Uber
• Setan alarm
• Turn off the lights
• Hear bank accountbalance
Convenience
• Listen to a recipe while cooking
• Make a call while driving
• Hear the headlineswhile you’re
dressing for work
• Ask for the definition of a word
when you’re readinga book

1. Map out the omnichannel journey
2. Define the personality
3. Act it out and test (Wizard of Oz)
4. Design functionality with user flows
5. Test and refine
Process

Map out the
omnichannel journey
• How can you leverage different
touch-points to shape expectations?
• How will context affect the
experience in different parts of the
journey?

Define the personality
• Reflect the core attributes of your
brand
• If the platformdoesn’t make the
distinction between the character of
the assistant and your product clear,
don’t deviate from the default
personality

Alexa acts as an intermediarybetween the
user and the brand
Google Assistantpasses the userover to a
different character
Uber: “Hi, this is Uber, there’s an Uber less than a
minute away…”
Alexa: “There’s an Uber less than a minute away,
would you like me to order it?”

Act it out and test
• Write down a basic script for the core
parts of the experience. Act it out or
use voice simulators
• User test early ideas using the WOZ
technique

Map out the
functionality
• Map out the all the different
steps, the ways user can
phrase their input and
technical considerations
• Work closely with
stakeholders

Test and refine
• Try to recruit participants who are familiar with Alexa.
If you can’t invest time in the beginning of the session
to familiarise them with the interface and the device.
• For usability tweaks, guerrila testing can work well

Voice usability tips
• Speak naturally: Avoid things like “Tocontinue sayContinue”
• Use the “one-breath” test
• Don’t present more than 3 options
• Use conversation markers: “got it”, “halfway there”,“next”
• Make the distinction between “I didn’t hear” vs. “I heard but I don’t
understand” clear

Learnings
• Users will expectpersonalisedexperiences.If possible offer account-linking
with the accountof the brand.
• Users need reassurancethatsensitive information is safe
• Users try to find shortcuts
• The more open ended the skill is the higher the likelihood of errors
• Be careful of free entry input. Alexamatches your utteranceto the closest
word she knows.

Resources
Amazon – Voice design bestpractices
Google– Design principles for actions
Design guidelines
Microsoft– Voice design bestpractices
Literature
Tools
SaySpring - Voice Prototyping
VoiceLabs- Analytics

“Jarvis, rotate
the hologram
80 degrees”
vs

3 key takeaways
• Voice interfaces are less usablethan GUI for most cases becausevoice is
transient and invisible
• Theyare greatfor speed and convenience in certain contexts
• The future is multi-modal

StratisValachis@gmail.com
Get in touch
@stratisvx