One second, uh. In 2019, an idea was given voice.
Hi I'm Q the world's first genderless voice assistant. It's not you know, it's not that
it can't be done; it can be done. Share my voice with Apple, Amazon, Google and Microsoft.
Synthetic voices from these companies live on over 2 billion devices worldwide. Some experts say that
by 2024 there will be more voice assistants on the planet than people. Covid-19 has accelerated
that. Q will soon be able to say anything, but it started as a call to action for synthetic voices
to reflect human diversity as they start to sound more and more and human. And together can ensure
that technology recognizes us all. The humans behind Q aren't the only ones pushing for this.
Nobody wants to wear a prosthetic limb that is just that someone else's or it doesn't fit them.
They want something that is molded for them. It's personalized for them. Dr. Rupal Patel is
a speech scientist at Northeastern University who founded a company called VocalId in 2014.
That was after a conference where she noticed that many attendees spoke with different assistive
devices but the same synthetic voice. [machine] It was a beautiful day. So basically what this is
is a it's a voice prosthesis for someone who's unable to speak so that's when we started the
technology and now we're making artificial voices for all sorts of things that also talk.
My name is Meghan and I'm on my way to Boston to get a new voice. Well, actually I'm the new voice.
I wanted to learn where these voices come from so i asked VocalId to make one for me. We created
this passage part of it is your synthetic voice and part of it is from your original recordings.
So am i supposed to guess which... You can try. I've looked and looked everywhere to
find another. I went down to the park and looked behind the trees. It's really hard
to tell which part is me and which is...can I actually hear it again? Making speech with the
machine is called "speech synthesis." Okay, it's asking me to make an on noise for three seconds.
To get the most human sounding voice possible you need to feed the machine a human voice.
So I sat down to record samples of my voice to VocalId's website--2000 sentences--which I chose
from their library of stories and speeches. I didn't quite know what i was getting myself
into. I was ambitious at first. I inquired what sort of talk I ought to make. I've never said so
much in one sitting, much less to an empty room. I got tired. My voice got tired. I went through
coffee. I went through cough drops. I devolved to shorter and simpler sentences. Fire is wonderful.
The sky is blue. When I finally got to 2000 I felt like I had finished a marathon. I'm sure it wasn't
an enjoyable experience really sitting there recording 2000 sentences, but the more data
you have the better it sounds. With just 1000 sentences, my new voice would have been clear
and intelligible, but it probably wouldn't have sounded like me. People emote spontaneously,
so if you didn't record any you know real questions or shout or anger, it's not going to
know how to do that. With 2000 sentences something begins to happen. It starts to sound more human
and at times almost indistinguishable from my voice. Do i sound like you? Do i sound human
to you? Do i sound real to you? So what happens between one thousand and two thousand sentences.
Basically to answer that we need to ask a bigger question: what makes a voice human? The voice
carries a lot of information about your age, your size, your habits. So are you a smoker? Are you a
loud talker? Do you abuse your voice? Do you yell a lot? It's all in the voice. Go ahead.
Okay and you are a Coco--fairly soft over-pitched voice, you're fairly breathy, and most of the
sound is coming out through your oral cavity versus your nasal cavity. Cocoa, beach ball,
feather, candy, lighthouse, armor, steam--these are voice types, an unofficial taxonomy that
VocalId created to showcase the variety inherent in the human voice. We hear voices of all these
different types around the world. What's your voice type? My voice type--I change between
brook most of the time and sometimes candy, and I think a lot of that just depends on how
much energy I have. When we talk our vocal cords vibrate with air pushed from the lungs. And then
we form words with our mouth, tongue and lips. But first it passes through the larynx or the voice
box where we control loudness and pitch. Even in the womb babies pick up on the importance of tone.
Ehat makes a voice human isn't just about what's said but how it's said. This is called prosity.
It's the pitch, the loudness, the durational changes that give speech meaning. Sometimes people
think of it as the icing on the cake, so you have the message and now it's how you modulate that
message. But i really think it is the it's the scaffolding that gives meaning to the message. It
tells us what's important in a way that speech can't alone. This is why we write with capitals,
exclamation points, underlining, bold, italics and emojis. Punctuation is just
an approximation for how we modulate our voice. Prosody is also how we communicate emotion. One
study showed that humans can identify these 24 distinct emotions through vocal sounds alone.
Another study found that people were better at reading others emotions when they heard just their
voice than when they could also see them. For over two decades now, synthetic voices have been
evaluated not only on intelligibility but also on how human they sound on a scale of one to five
and it's been a windy road to get closer to five.
This is a replica of a speaking machine first fashioned in 1769 with parts of a bagpipe and a
clarinet. It's a crude version of articulatory synthesis or an attempt to model the human
vocal apparatus. Fast forward to 1939 and you have the first electronic speech synthesizer
the voder or voice operating demonstrator premiered at the 1939 World's Fair.
The machine uses only two sounds produced electrically one of these represents the breath.
The other the vibration of the vocal cords.
The keys filtered those sounds a pedal modulated the pitch. Who did she see? She saw me.
Did she see you or hear you? She saw me. The voder took operators a whole year to learn how to play.
It never caught on but it helped inspire formant synthesis named for the frequency bands found
in different sounds. We ffilter formants by changing the shape of our vocal tract.
This method would eventually be used to create Stephen Hawking's voice. Bringing science to the
people brings people into science. Then there's concatenative synthesis. This method uses human
recordings like this one as raw material. Those recordings are chopped up into tiny units of sound
called phonemes, which programmers basically copy and paste to form new sentences.
So for a long time synthetic voice had gotten to a plateau today we use machine learning
based methodologies where you try to learn the parameters that are changing for every different
sound that is being produced and then you try to recreate that speech. The most advanced methods
train a neural network on raw waveforms at tens of thousands of samples per second. Google says
their voice is top four on the natural scale in both North American English and Mandarin Chinese.
It's still not five, but it can model any voice in any language. And one other
highly human audio output--music. But especially to a trained ear,
the machines can't quite pull off what some humans can. I've heard stuff that sounds like Mozart.
I've even heard stuff that sounds kind of like the Beatles. But it's missing something fundamental,
some human quality. Maybe what's still missing in synthetic speech requires machines to not
only mimic, but also feel like humans. As a neuroscientist, I believe that all of our
thoughts and feelings and hopes and desires come from the firing of neurons. We still don't have
a good idea of how to model one artificial neuron, let alone 80 billion of them connected together in
the ways that human neurons are or at least in a way that will facilitate human-like learning
and creativity. Potential is there, but for now I haven't heard a single AI-generated piece of music
that I like. And maybe that's a good thing for any kind of sound that humans can make. Today we
actually see this box. We see this thing talking to us, but what if it was really everywhere?
I think ideally it's when these technologies allow you and I,
two humans, to communicate more effectively rather than via the machine.