Designing Voice User Interfaces: Principles of Conversational Experiences

278 Pages·2016·16.15 MB·English

by  Cathy Pearl

D esigning
Voice User
Interfaces
PRINCIPLES OF CONVERSATIONAL EXPERIENCES
Cathy Pearl

Praise for Designing Voice
User Interfaces
“Voice has been core to human interaction since well before history.
But what is old is now new: voice is becoming core to how we
interact with computers. Pearl has done an brilliant job of distilling
her 17 years of experience into a gem of a book. Valuable lessons,
clear thinking, and insightful observations frame a core argument
about how to design for voice. A completely new approach to an
ancient interaction.”
MARK STEPHEN MEADOWS, AUTHOR, ARTIST,
AND PRESIDENT OF BOTANIC.IO
“This book is a great resource for learning the fundamentals of voice
user interface design. More and more designers are going to be
expected to design usable voice experiences and Designing Voice
User Interfaces can help you to learn how to do just that.”
CHRIS MAURY, FOUNDER, CONVERSANT LABS
“Practical and comprehensive, Cathy Pearl’s book about VUI design
clearly originates from her vast amount of hands-on experience.
This book passes on her years of lessons learned so you can start your
own adventures with speech interfaces from an advantaged position.”
REBECCA NOWLIN GREEN, NUANCE COMMUNICATIONS,
BUSINESS CONSULTING
“Sharing with lively swagger her lifelong passion for machines that listen
and talk, Pearl ushers in the new era of VUI design with impressively broad
and practical coverage. Since designing for speech has special challenges
and implications that elude even industry “insiders,” this book promises to
be worthwhile as well for business decision-makers and developers who work
in this space. With multimodal apps now a cultural fixture, chatbots on the
horizon, and virtual assistance making its revival (remember Wildfire and
General Magic’s Portico of the 90s?), this release couldn’t be more timely.”
JAMES GIANGOLA, CREATIVE LEAD,
CONVERSATION DESIGN & DIRECTION, GOOGLE
“Pearl’s Designing Voice User Interfaces is a refreshing and much-needed
update on how to design effective VUIs. The book is brimming with practical
advice from experts and packed with examples that reference leading-edge
technology. The book deserves a place on any VUI designer’s desk.”
JENNIFER BALOGH, PH.D., COAUTHOR
OF VOICE USER INTERFACE DESIGN
Designing Voice User
Interfaces
Principles of Conversational Experiences
Cathy Pearl
Beijing Boston Farnham Sebastopol Tokyo
Designing Voice User Interfaces
by Cathy Pearl
Copyright © 2017 Cathy Pearl. All rights reserved.
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December 2016: First Edition
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2016-12-06 First release
See http://oreilly.com/catalog/errata.csp?isbn=0636920050056 for release details.
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978-1-491-95541-3
[LSI]
To my friend Karen Kaushansky, who always
encourages me to take the meeting.

[ contents ]
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Chapter 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
A Brief History of VUIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Conversational User Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . 5
What Is a VUI Designer? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Chatbots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 2 Basic Voice User Interface Design Principles . . . . . . . . . . 13
Designing for Mobile Devices Versus IVR Systems . . . 13
Conversational Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Setting User Expectations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Design Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Confirmations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Command-and-Control Versus Conversational . . . . . . . . 32
Conversational Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Error Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Don’t Blame the User . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Novice and Expert Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Keeping Track of Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Help and Other Universals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Disambiguation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
vii
Design Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Accessibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Chapter 3 Personas, Avatars, Actors, and Video Games . . . . . . . . . . 71
Personas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Should My VUI Be Seen? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Using an Avatar: What Not to Do . . . . . . . . . . . . . . . . . . . . . . 77
Using an Avatar (or Recorded Video): What to Do . . . . . 79
When Should I Use Video in My VUI? . . . . . . . . . . . . . . . . 86
Visual VUI—Best Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Visual (Non-Avatar) Feedback . . . . . . . . . . . . . . . . . . . . . . . . . 95
Choosing a Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Pros of an Avatar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
The Downsides of an Avatar . . . . . . . . . . . . . . . . . . . . . . . . . .101
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104
Chapter 4 Speech Recognition Technology . . . . . . . . . . . . . . . . . . . . . . 107
Choosing an Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Barge-In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
N-Best Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
The Challenges of Speech Recognition . . . . . . . . . . . . . . . 122
Data Privacy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128
Chapter 5 Advanced Voice User Interface Design . . . . . . . . . . . . . . . 129
Branching Based on Voice Input . . . . . . . . . . . . . . . . . . . . . 130
Disambiguation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Handling Negation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Capturing Intent and Objects . . . . . . . . . . . . . . . . . . . . . . . . 141
Dialog Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Don’t Leave Your User Hanging . . . . . . . . . . . . . . . . . . . . . . 144
Should the VUI Display What It Recognized? . . . . . . . . 144
Sentiment Analysis and Emotion Detection . . . . . . . . . .146
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