"My name is... my name is...": A Linguistic Map for Voice Agents — Midam Kim, ServiceNow
Read the talk
A Linguistic Map for Voice Agents
Midam Kim explains how recognition, pronunciation, timing, and shared understanding work together—and how failures across those layers can turn a simple account lookup into a request for a human.
From a talk by Midam Kim
At a glance
Ideas worth remembering
Diagnose listening and speaking separately across sounds, words, interaction, and mental model. A correctly recognized spelling can still lead to incorrect pronunciation, while reading an identifier can expose recognition and turn-timing failures together.
The layers are interdependent. Recognition, understandable language, appropriate timing, and intent tracking must align to support task completion.
A failed exchange needs useful repair. Asking for the same information again without interactive clarification can deepen frustration and prompt escalation to a human.
Design for the user's accumulating understanding across the call. Dynamic context retention, emotion handling, vocabulary, and timing must accommodate changing expectations.
The framework guides diagnosis rather than supplying a universal fix. Its longer-term challenge is to accommodate users who adapt to the agent and language that changes over months or years.
A simple call accumulates failures
Midam Kim, an ML engineer at ServiceNow and a researcher of speech communication in the wild, introduces linguistics as a way to understand voice AI failures. Her starting point is a call she experienced herself: an agent asks her to spell her first name, and she slowly supplies M I D A M. The agent confirms M I D A N instead. She corrects the final letter, but its next response still pronounces her name incorrectly. Acknowledging a correction has not produced a successful spoken response.
The agent then asks for an account number without establishing which identifier Kim should provide. She searches for it and starts reading an unfamiliar alphanumeric string, beginning A X 4 5 1. Reading takes time because she is not accustomed to the string. The bot interrupts, announces that it cannot find her record, and asks her to repeat the information. Rather than changing its approach after the failed attempt, it sends her through the same task again. Her irritation culminates in a request to speak to a person.
Kim presents this sequence as a familiar pattern of voice-agent failure. Her question is how to identify the actual problems before trying to mitigate them. Linguistics supplies an organizing framework: the misheard letter, incorrect pronunciation, unclear request, interruption, and unsuccessful repetition belong to different parts of communication, even though the user experiences them as one deteriorating call.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Conversation requires both parties to participate
Kim describes human communication as a joint activity. One person produces sounds and words; the other hears them and, in a conversation, responds with sounds and words of their own. Interaction carries this exchange back and forth. Throughout it, both participants continuously process and update their mental models. Communication therefore includes what each party understands about the exchange as it develops, alongside the utterances themselves.
She argues that communication between a human and a voice agent must support this same joint activity. People bring their established expectations of conversation to bots: they expect the other party to listen, respond, and maintain understanding as the exchange proceeds. A voice interface consequently has to accommodate the way humans communicate, rather than assume that producing an answer completes its responsibility.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Recognition, pronunciation, and repair fail differently
Revisiting the call, Kim separates listening from speaking for each participant. Confusing M with N is a listening failure: the agent does not correctly distinguish what she supplies. The pronunciation problem belongs to its speaking channel. Kim attributes that problem to text-to-speech applying English-centric reading rules to her name. These are distinct mechanisms; correctly retaining the letters does not by itself ensure that the system will pronounce the resulting name appropriately.
Kim initially tolerates the pronunciation problem because it also occurs with people. She adapts again when the account-number request confuses her: she looks for the identifier and begins reading it. Her diagnosis is that speech-to-text does not recognize the word unit correctly, after which the agent cuts her off and talks over her. The example connects recognition with interaction timing. The system must allow the user to finish supplying the relevant unit, even when doing so involves a slow, unfamiliar reading.
The request for repetition exposes another failure. To Kim, it shows that the agent is not tracking a mental model with her: it does not respond constructively to what has just gone wrong. She identifies interactive clarification as a common human repair strategy that the agent fails to try. Repetition requests can therefore become frustrating when they do not help resolve the underlying uncertainty. At this point she chooses a human rather than continuing the exchange.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Two channels across four levels
The framework crosses two channels—listening and speaking—with four levels: sounds, words, interaction, and mental model. Its eight cells turn broad complaints about an agent into more specific diagnostic questions. On the listening side, the sound-level question is whether the bot recognizes the user's speech well. At the word level, the question is whether it understands the user's words. Hearing the signal and understanding what it conveys are separate responsibilities.
Listening at the interaction level means waiting until the appropriate time for the bot's turn. At the mental-model level, it means understanding the user's intention. These questions extend listening beyond speech recognition: an agent can receive words while still failing to determine whether the user has finished or what the user is trying to accomplish.
The speaking channel mirrors those responsibilities. At the sound level, the concern is pronunciation. At the word level, the bot must choose language the user can understand. At the interaction level, it must speak at the right time. At the mental-model level, it must provide information the user actually needs. Kim uses this arrangement to give engineering, linguistic, and cognitive-science concerns a place in the same framework.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
The cells must work together
Kim stresses that the components are interdependent. Work on sounds must account for words; work on sounds and words must also account for interaction, including turn taking and turn detection. The map distinguishes responsibilities so that engineers can diagnose them, but the responsibilities still have to align during the conversation. Improving one layer in isolation leaves the others able to undermine the result.
She places task completion at the mental-model layer and argues that it depends on all the preceding components. Understanding the goal is insufficient if the agent cannot reliably handle the speech, words, or timing needed to reach it. Her design requirement is alignment across the layers: the whole exchange must support completion, rather than merely contain individually capable components.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Speech disappears while understanding accumulates
The framework also operates over time. In chat, the user can see the history as text. In the voice experience Kim describes, the participants exchange utterances, but the air vibrations carrying them disappear. Her contrast concerns what remains available to the user during the interaction: speech does not leave the same visible conversational record as chat.
What persists, in Kim's account, is the user's mental model. Sounds, words, and interactions pass, while the user's understanding proceeds and grows across the call. She therefore identifies that accumulating mental model as the target for satisfaction. The agent's responses must meet the user's developing expectations over time, rather than be assessed only as isolated spoken outputs.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Manage the conversation dynamically
Kim translates the framework into several areas of engineering work. For recognition, she recommends choosing good automatic speech recognition models and configurations, along with post-processing. For speech generation, she points to text-to-speech models, configurations, and pre-processing. She also calls for carefully curating vocabulary that the bot and user can share. These are complementary interventions: model selection addresses part of the system, while processing and shared language address how that capability participates in a conversation.
Timing requires attention to turn detection, latency, and turn taking. Kim also recommends emotion detection and handling, together with context retention. By context, she means context across all these components. Retaining conversational context therefore has a broader role than preserving the words alone: it must support the changing interaction the agent is managing.
This management has to be dynamic because conditions change during a call. Different people, including children, bring different expectations; the system must respond when people are unhappy as well as when they are happy. Kim makes that ongoing adaptation a condition of scalable voice-AI orchestration and acknowledges that it is difficult. Voice feels natural to people because linguistic coordination supports it, but building that coordination into an agent is demanding.
Kim connects these linguistic concerns to business outcomes: user frustration, task failures, escalation to live agents, abandoned calls, and silent failures. She presents reducing those outcomes as a reason to attend to the framework, without supplying measured reductions. She also mentions an end-to-end benchmark developed at ServiceNow for diagnosing voice agents, but does not explain its evaluation procedure or report results here.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
A diagnostic framework must accommodate change
Kim closes by returning to voice AI as a joint activity between bot and user, with needs served across multiple layers in real time. She explicitly offers no universal fix. The framework is a way to diagnose a particular system and build upon that diagnosis; the remedy depends on the system itself. Alongside trying the benchmark, she recommends learning linguistics and hiring linguists. Her business argument follows from voice being a linguistic, human, and cognitive experience: decisions about communication affect operational outcomes.
Her longer-term question starts with adaptation between people. During the talk, listeners have become familiar with her speaking style, accent, and vocabulary. She suggests that this attention could make a future conversation with her more comfortable. Users likewise adapt to a voice agent throughout a call. The design question is whether the system is ready for that adaptation to help them use it better the next time. Kim poses this as a requirement to consider, rather than presenting an implemented mechanism for learning across encounters.
The final question expands adaptation beyond an individual call: language itself changes. Kim asks whether an agent is ready for language change in one year, or even six months. The challenge is to keep the system responsive as the language it encounters evolves. She ends the talk with that question open.
Suggest correction
This note stays in this page until you copy or download it. Nothing is submitted; reloading clears the draft.
Read the complete timestamped transcript
- 0:01
[music]
- 0:12
>> Okay, hello everyone.
- 0:16
So,
- 0:19
my name is Midam Kim. I am an ML
- 0:22
engineer from ServiceNow and I'll be
- 0:25
talking about a linguistic framework for
- 0:28
voice AI.
- 0:33
So,
- 0:35
quick background of me so you know where
- 0:37
I'm coming from.
- 0:39
Like I said, I'm an ML engineer at
- 0:41
ServiceNow, but I'm also a researcher,
- 0:43
lifelong researcher, of speech
- 0:45
communication in the wild.
- 0:47
So, my motto is doing linguistics and
- 0:51
what I'm going to be doing today is to
- 0:54
hand you that lens of linguistics.
- 1:00
So, have you experienced voice AI
- 1:03
failures?
- 1:05
Yeah, like everyone.
- 1:06
>> [laughter]
- 1:10
>> So, I'm going to introduce an example
- 1:12
that I experienced myself.
- 1:15
So, the bot asked me, "Could you please
- 1:18
spell your first name?"
- 1:20
And then I slowly start to spell my
- 1:23
name.
- 1:24
Yes, it is m i d a m.
- 1:29
And the bot says, "Confirming with you,
- 1:31
is it m i d a n?"
- 1:35
And then I say, "No, it is m i d a m."
- 1:41
Um
- 1:42
and the bot says,
- 1:44
"Thank you for your correction. Happy to
- 1:46
help you today, Madam."
- 1:48
And I then I
- 1:50
get slightly annoyed, more annoyed,
- 1:51
because my name is Midam, not Madam.
- 1:55
And then it asked me about, "Now, what
- 1:57
is your account number?
- 1:59
And then, I start start getting
- 2:01
confused. What is that account number
- 2:03
thing?
- 2:04
And then,
- 2:06
I try to find uh information about that.
- 2:10
So,
- 2:11
which one? Um it must be and I start
- 2:16
uh
- 2:17
slowly start spelling the account
- 2:20
number. So, it is A X 4 5 1.
- 2:25
And then, I take time because I'm not
- 2:28
used to reading this strange number.
- 2:32
And then, the bot cuts me off.
- 2:34
And then, it says, I couldn't find your
- 2:36
record.
- 2:37
And then, without even trying, it asked
- 2:40
me to repeat that again. Can you please
- 2:42
repeat that? And then, I get super
- 2:44
annoyed and then, I can say, can I talk
- 2:46
to a person?
- 2:48
I just don't want to deal with you
- 2:49
anymore.
- 2:50
So, this is a very typical pattern of
- 2:53
voice AI, unfortunately, at this point.
- 2:56
So, I just want to navigate how we can
- 2:59
solve this problem
- 3:01
with linguistics.
- 3:06
So, voice AI is booming.
- 3:08
But users are still often preferring
- 3:10
human agents over voice agents.
- 3:13
How can we mitigate this issue?
- 3:17
But in the first place, what are the
- 3:19
actual problems?
- 3:21
So, I think we can think about a
- 3:23
fundamental frame framework to
- 3:25
understand this into an architecture of
- 3:28
voice AI,
- 3:29
which is called linguistics.
- 3:34
So, as all of us already know,
- 3:38
human communication is a joint activity,
- 3:41
like the thing that we're doing right
- 3:42
now.
- 3:43
So, I give you my sounds and words.
- 3:47
You hear them.
- 3:49
And then, if it is a conversation,
- 3:51
you're going to give me your sounds and
- 3:53
your words.
- 3:55
And then this is going back and forth
- 3:58
through interaction.
- 4:01
And then in this process, we're
- 4:03
continuously
- 4:04
processing and updating our mental
- 4:07
models.
- 4:09
So that's a joint activity
- 4:12
for human communication.
- 4:14
And I would like to say
- 4:17
in the voice AI human communication,
- 4:20
it also has to be a joint activity like
- 4:23
this.
- 4:24
Because that's the only thing that we
- 4:27
know about human communication as a
- 4:29
human being. We have been evolving
- 4:31
thousands of years as communicators, and
- 4:34
this is what we know. So we expect the
- 4:36
same thing to bots.
- 4:41
So let me go over the failure scene of
- 4:44
my call with the voice agent
- 4:47
in this framework.
- 4:49
So you see there's listen
- 4:52
and speak for each party.
- 4:57
So I start spelling my first name.
- 5:00
And then the bot did not hear that the
- 5:04
difference between M and N correctly, so
- 5:07
it's an
- 5:08
SCT failure in the listening level.
- 5:12
And then the TTS applies only
- 5:15
English-centric reading rules to my
- 5:17
name, M I D A M, would read it as Midam
- 5:21
in the
- 5:22
American English version.
- 5:25
So I'm confused, but at this time I'm
- 5:27
kind of generous because that happens a
- 5:29
lot even with human beings. So I'm okay.
- 5:34
But then when it brought
- 5:35
brought up account number thing
- 5:38
because I don't know what that is,
- 5:40
I'm confused again.
- 5:42
But I'm adaptive, I can find I can look
- 5:45
for it.
- 5:46
So I found the number, start reading it,
- 5:48
but
- 5:50
the STT did not recognize the word unit
- 5:53
correctly, so
- 5:54
it cuts me off, and uh
- 5:58
uh finally, it's uh eventually talked
- 6:02
over me.
- 6:03
So, I get
- 6:05
really irritated.
- 6:08
And then, when it asked me for the
- 6:09
repetition of the same information, and
- 6:13
then, it is clear that the spot is not
- 6:15
tracking the mental model with me.
- 6:18
And then, very rudely, it's uh does not
- 6:22
even try interactive clarification,
- 6:24
which is a common strategy by human
- 6:26
beings.
- 6:27
So, I don't want to deal with this
- 6:29
anymore, so I say, "Can I talk to a
- 6:30
person?"
- 6:34
So,
- 6:35
let's go over the uh the framework
- 6:37
again. So, the these are the linguistic
- 6:39
components that are expected and well
- 6:41
maintained in human-to-human voi- uh
- 6:45
uh conversation.
- 6:47
So, there are listening channels, a
- 6:49
listening channel and speaking channel,
- 6:50
and there are different components like
- 6:52
sounds, words, interaction, and mental
- 6:54
model.
- 6:55
So, the first component is, does the bot
- 6:58
recognize the user's speech well?
- 7:01
And all of these technical terms
- 7:04
uh will fall under this.
- 7:07
And then, there was there's going to be
- 7:08
this second component, which is words in
- 7:11
the listening channel. So, does the bot
- 7:13
understand the user's words?
- 7:17
And then, the third one is, does the bot
- 7:19
wait until the right timing to for its
- 7:22
turn? It's about It's going to be about
- 7:24
uh listening channel interaction.
- 7:28
And then, uh the last part is mental
- 7:31
model. So, does the bot understand the
- 7:33
user's intention
- 7:35
in the listening part?
- 7:38
And then, we can also go to the speaking
- 7:39
channel, so it's going to be about
- 7:41
pronunciation for the sound.
- 7:43
And also there's about understand the
- 7:46
the words users are
- 7:49
uh there's about choose the words the
- 7:51
user can understand.
- 7:53
And in the interaction part, there's
- 7:55
about speak with the right timing.
- 7:58
And lastly, there's about speak with the
- 8:01
information the user actually need.
- 8:05
So, there are a lot of engineering or
- 8:08
linguistic or cognitive science terms
- 8:10
that are in here that that are here. Um
- 8:14
you can see now see that all of those
- 8:17
have their right spots in this
- 8:18
linguistic framework.
- 8:23
And importantly, these components are
- 8:24
interdependent,
- 8:26
not separate or uh independent from each
- 8:29
other. They're interdependent and
- 8:31
they're aligned. So, when you want to do
- 8:34
good things about sounds,
- 8:37
you have to think about words level.
- 8:39
And then when you want to do good things
- 8:41
about these sounds and words,
- 8:43
you also have to uh account for
- 8:46
interaction, so turn taking or turn
- 8:48
detection.
- 8:50
And then finally, you want to uh have
- 8:53
good uh task completion, which is the
- 8:56
goal of these mental model uh layer.
- 8:59
Then you have to have all of these.
- 9:02
Without all of those, without any of
- 9:04
those, any of those components, your
- 9:06
voice agent will fail.
- 9:09
And then finally,
- 9:11
uh it has to be well aligned. All of
- 9:13
these have to be well aligned.
- 9:17
And additionally, you have to keep your
- 9:20
mind keep in mind that
- 9:22
this is happening on the timeline.
- 9:26
What I mean by that is it is silently
- 9:29
tracked. Unlike in chat, in chat you see
- 9:33
the history of what was said
- 9:35
uh as text.
- 9:37
But in voice agent experience,
- 9:40
uh, you say something, and the bot says
- 9:42
something, you go back and forth,
- 9:45
and then see, all these waveforms, the
- 9:49
air via the vibration in the, uh, in the
- 9:51
air, they're all gone.
- 9:53
And only the user's mental model is the
- 9:56
thing that's left, and that matters.
- 10:00
So, sounds, words, interactions vanish
- 10:03
the moment they're spoken,
- 10:04
but the mental model proceeds and grows
- 10:07
over the timeline.
- 10:09
So, this is what you have to
- 10:12
target
- 10:14
for user satisfaction.
- 10:16
And then, what can we do
- 10:19
for the bot to meet the standard of the
- 10:22
user?
- 10:25
So, what we can do, uh, would include,
- 10:28
of course, choosing good ASR models or
- 10:31
configurations and do some
- 10:32
post-processing,
- 10:34
uh, choosing good TTS models,
- 10:36
configurations, and pre-processing,
- 10:38
and, uh, carefully curate the vocabulary
- 10:42
that can be shared between the bot and
- 10:44
the user,
- 10:45
and do good job of a turn-to-turn
- 10:48
detection, latency, and turn-taking.
- 10:52
Um, and very importantly, we have to, it
- 10:56
would be great if we can do good emotion
- 10:57
detection and handling, and context
- 11:00
retention, and by context, what I mean
- 11:02
is context about all of these.
- 11:07
And importantly,
- 11:09
uh, it has to be dynamic because things
- 11:12
are always changing, uh, throughout over
- 11:14
the course of the call. So, we would
- 11:17
have to do this management dynamically
- 11:19
along the timeline
- 11:21
for different kinds of people.
- 11:23
So, kids or different kinds of people
- 11:26
like these will have different
- 11:28
expectations that we have to satisfy.
- 11:32
Uh, not just when they're happy, but
- 11:34
also when they're not happy.
- 11:36
So, only then you can pursue a dynamic
- 11:39
and truly scalable orchestration of
- 11:41
voice AI.
- 11:43
So, it's a very difficult job to do.
- 11:48
We always say that voice is the most
- 11:50
natural way of communication, but it is
- 11:53
not actually not easy. Behind the scene,
- 11:55
it is thanks to this linguistic
- 11:57
orchestration.
- 11:59
When your bot is not good at it,
- 12:01
it's a catastrophic failure.
- 12:06
Um, so paying attention to this
- 12:09
linguistic framework would have lots of
- 12:12
business implications because then you
- 12:14
can uh
- 12:17
decrease all of these user frustration,
- 12:19
task failures, live agent escalation, or
- 12:22
abandoned calls, or silent failures.
- 12:28
So, in ServiceNow, we have made a a good
- 12:32
uh benchmark end-to-end benchmark called
- 12:34
Eva bench. So, you can try that to
- 12:36
diagnose your voice agent's uh status.
- 12:43
Um, key takeaways.
- 12:45
So, voice AI is a joint activity between
- 12:50
the bot and the user, not just a
- 12:52
pipeline.
- 12:54
And we must serve users' needs in
- 12:55
multiple layers real time.
- 12:59
It's not that I have given you a fix
- 13:01
today because there's nothing like that.
- 13:04
It just uh the fix is in you and your
- 13:07
system.
- 13:09
But, what I have given you is today is
- 13:14
the linguistic framework you can try to
- 13:16
diagnose your system
- 13:18
and to build your system upon.
- 13:21
You can try Eva, but also you can learn
- 13:24
linguistics and hire linguists.
- 13:27
Um, another thing I want to remind you
- 13:29
of is that business implications are
- 13:32
linguistic implications and vice versa
- 13:35
in this voice AI scene. Because voice is
- 13:39
fundamentally a linguistic and very
- 13:41
human and cognitive experience.
- 13:46
I would like to ask you a longer term
- 13:48
question.
- 13:50
Speakers adapt. So, I
- 13:54
I'm pretty sure that in this talk in my
- 13:58
talk with you guys today, you have
- 14:00
learned something about me, about my
- 14:02
speaking style, what kind of accents I
- 14:04
speak, what kind of words I'm using. So,
- 14:07
next time I see you guys in person, you
- 14:10
would find it more comfortable to talk
- 14:12
to me because you have paid attention to
- 14:14
me.
- 14:15
Right? So, speakers are always adapting.
- 14:17
So, the user will be adapting to your
- 14:20
voice agent throughout the call. So, is
- 14:24
your system ready for them to
- 14:27
use you better, use it your voice agent
- 14:29
better the next time?
- 14:31
And
- 14:32
language is always change. So, is your
- 14:35
voice agent ready for language change in
- 14:38
1 year or 6 months even?
- 14:44
So, thank you.
- 14:47
>> [applause]