Developing with Speech and Voice Recognition in Mobile Apps

M3Conference

Developing with Speech and
Voice Recognition in Mobile Apps
Nick Landry, MVP
App Artisan
Nokia Developer Champion & Ambassador
activenick@mobility42.com
@ActiveNick – www.mobility42.com

talk2me

Who is ActiveNick?
• App Artisan – Mobile Development Consultant – Mobility42
• Microsoft MVP: Windows Phone Development
• Mobile Publisher – Big Bald Apps: http://www.bigbaldapps.com
• Nokia Developer Champion and Ambassador
• Speaker. Blogger. Author. Tweeter. Gamer

• 20+ Years of Professional Experience
• Specialties:
• Mobile Development
• Location Intelligence & Geospatial Systems
• Data Visualization, HPC, Cloud
• Mobile Game Development
• Blog: www.ActiveNick.net

• Twitter: @ActiveNick

Agenda
• Speech on Windows Phone 8
• Speech synthesis
• Controlling applications using speech
• Voice command definition files
• Building conversations
• Selecting application entry points
• Simple speech input
• Speech input and grammars
• Using Grammar Lists

Windows Phone Speech Support
• Windows Phone 7.x had voice support built into the operating system
• Programs and phone features could be started by voice commands e.g “Start MyApp”
• Incoming SMS messages could be read to the user

• The user could compose and send SMS messages
• Windows Phone 8 builds on this to allow applications to make use of speech
• Applications can speak messages using the Speech Synthesis feature
• Applications can be started and given commands
• Applications can accept commands using voice input

• Speech recognition requires an internet connection, but Speech Synthesis does not

Enabling Speech Synthesis
• If an application wishes to use speech output the
ID_CAP_SPEECH_RECOGNITION capability must
be enabled in WMAppManifest.xml
• The application can also reference the Synthesis
namespace
using Windows.Phone.Speech.Synthesis;

Simple Speech
async void CheeseLiker()
{
SpeechSynthesizer synth = new SpeechSynthesizer();
await synth.SpeakTextAsync("I like cheese.");
}

• The SpeechSynthesizer class provides a simple way to produce speech
• The SpeakTextAsync method speaks the content of the string using the default voice

• Note that the method is an asynchronous one, so the calling method must use the
async modifier
• Speech output does not require a network connection

Selecting a language
// Query for a voice that speaks French.
var frenchVoices = from voice in InstalledVoices.All
where voice.Language == "fr-FR"
select voice;
// Set the voice as identified by the query.
synth.SetVoice(frenchVoices.ElementAt(0));

• The default speaking voice is selected automatically from the locale set for the phone
• The InstalledVoices class provides a list of all the voices available on the phone

• The above code selects a French voice

Demo 1: Speech Synthesis
and Voice Selection
talk2me - http://bit.ly/wpt2m

Speech Synthesis Markup Language
<?xml version="1.0" encoding="ISO-8859-1"?>
<speak version="1.0"
xmlns=http://www.w3.org/2001/10/synthesis xml:lang="en-US">
<p> Your <say-as interpret-as="ordinal">1st</say-as> request was for
<say-as interpret-as="cardinal">1</say-as> room on
<say-as interpret-as="date" format="mdy">10/19/2010</say-as> ,
arriving at <say-as interpret-as="time" format="hms12">12:35pm</say-as>.
</p>
</speak>
• You can use Speech Synthesis Markup Language (SSML) to control the spoken output
• Change the voice, pitch, rate, volume, pronunciation and other characteristics
• Also allows the inclusion of audio files into the spoken output
• You can also use the Speech synthesizer to speak the contents of a file

Controlling
Applications
using Voice
Commands

Application Launching using Voice command
• The Voice Command feature of Windows Phone 7 allowed users to start applications
• In Windows Phone 8 the feature has been expanded to allow the user to request data
from the application in the start command
• The data will allow a particular application page to be selected when the program starts
and can also pass request information to that page

• To start using Voice Commands you must Create a Voice Command Definition (VCD) file
that defines all the spoken commands
• The application then calls a method to register the words and phrases the first time

it is run

The Fortune Teller Program
• The Fortune Teller program will tell
your future

• You can ask it questions and it will
display replies
• It could also speak them

• Some of the spoken commands activate
different pages of the application and
others are processed by the application

when it starts running

The Voice Command Definition (VCD) file
<CommandPrefix> Fortune Teller </CommandPrefix>
<Example> Will I find money </Example>
<Command Name="showMoney">
<ListenFor> [Will I find] {futureMoney} </ListenFor>
<Feedback> Showing {futureMoney} </Feedback>
<Navigate Target="/money.xaml"/>
</Command>
<PhraseList Label="futureMoney">
<Item> money </Item>
<Item> riches </Item>
<Item> gold </Item>
</PhraseList>
• This is the “money” question: “Fortune Teller Will I find money”

</Command>
<Item> gold </Item>
</PhraseList>

• This is the phrase the user
says to trigger the
command
• All of the Fortune Teller
commands start with this
phrase

</Command>
<Item> gold </Item>
</PhraseList>

• This is example text that
will be displayed by the
help for this app as an
example of the commands
the app supports

</Command>
<Item> gold </Item>
</PhraseList>

• This is the command
name
• This can be obtained from
the URL by the application
when it starts

</Command>
<Item> gold </Item>
</PhraseList>

• This is the example for this
specific command

</Command>
<Item> gold </Item>
</PhraseList>

• This is the trigger phrase for
this command
• It can be a sequence of
words
• The user must prefix this
sequence with the words
“Fortune Teller”

</Command>
<Item> gold </Item>
</PhraseList>

• This is the phraselist for the
command
• The user can say any of the
words in the phraselist to
match this command

• The application can
determine the phrase used
• The phraselist can be
changed by the application
dynamically

</Command>
<Item> gold </Item>
</PhraseList>

• This is the spoken feedback
from the command
• The feedback will insert the
phrase item used to
activate the command

</Command>
<Item> gold </Item>
</PhraseList>

• This is the url for the page
to be activated by the
command

• Commands can go to
different pages, or all go to
MainPage.xaml if required

</Command>
<Item> gold </Item>
</PhraseList>

• These are the phrases that
can be used at the end of
the command

• The application can modify
the phrase list of a
command dynamically
• It could give movie times
for films by name

Installing a Voice Command Definition (VCD) file
async void setupVoiceCommands()
{
await VoiceCommandService.InstallCommandSetsFromFileAsync(
new Uri("ms-appx:///VCDCommands.xml", UriKind.RelativeOrAbsolute));
}

• The VCD file can be loaded from the application or from any URI
• In this case it is just a file that has been added to the project and marked as Content
• The VCD can also be changed by the application when it is running
• The voice commands for an application are loaded into the voice command service when
the application runs
• The application must run at least once to configure the voice commands

Launching Your App With a Voice Command
• If the user now presses and holds the Windows button, and says:
Fortune Teller, Will I find gold?

the Phone displays “Showing gold”
• It then launches your app and navigates to the page associated with this command, which is
/Money.xaml
• The query string passed to the page looks like this:
"/?voiceCommandName=showMoney&futureMoney=gold&reco=Fortune%20Teller%Will%20I%20find%20gold"

Command
Name

Phaselist
Name

Recognized
phrase

Whole phrase as it
was recognized

Handling Voice Commands
if (e.NavigationMode == System.Windows.Navigation.NavigationMode.New) {
if (NavigationContext.QueryString.ContainsKey("voiceCommandName")) {
string command = NavigationContext.QueryString["voiceCommandName"];
switch command) {
case "tellJoke":
messageTextBlock.Text = "Insert really funny joke here";
break;
// Add cases for other commands.
default:
messageTextBlock.Text = "Sorry, what you said makes no sense.";
break;
}
}
}

• This code runs in the OnNavigatedTo method of a target page
• Can also check for the voice command phrase that was used

Identifying phrases
<Item> gold </Item>
</PhraseList>

string moneyPhrase = NavigationContext.QueryString["futureMoney"];
• The navigation context can be queried to determine the phrase used to trigger the navigation
• In this case the program is selecting between the phrase used in the “riches” question

Modifying the phrase list
VoiceCommandSet fortuneVcs = VoiceCommandService.InstalledCommandSets["en-US"];

await fortuneVcs.UpdatePhraseListAsync("futureMoney",
new string[] { "money", "cash", “millions", “piles of dough" });

• An application can modify a phrase list when it is running

• It cannot add new commands however
• This would allow a program to implement behaviours such as:
“Movie Planner tell me showings for Batman”

Recognizing Free Speech
• A Windows Phone application can recognize words and phrases
and pass them to your program
• From my experiments it seems quite reliable

• Note that a network connection is required for this feature if
you use the generic dictation grammar
• Your application can just use the speech string directly
• The standard “Listening” interface is displayed over
your application

Simple Speech Recognition
SpeechRecognizerUI recoWithUI;
async private void ListenButton_Click(object sender, RoutedEventArgs e)
{
this.recoWithUI = new SpeechRecognizerUI();
SpeechRecognitionUIResult recoResult =
await recoWithUI.RecognizeWithUIAsync();
if ( recoResult.ResultStatus == SpeechRecognitionUIStatus.Succeeded )
MessageBox.Show(string.Format("You said {0}.",
recoResult.RecognitionResult.Text));
}
• The above method checks for a successful response
• By default the system uses the language settings on the Phone

Customizing Speech Recognition
• InitialSilenceTimeout
• The time that the speech recognizer will wait until it hears speech

• The default setting is 5 seconds
• BabbleTimeout
• The time that the speech recognizer will listen while it hears background noise

• The default setting is 0 seconds (the feature is not activated)
• EndSilenceTimeout
• The time interval during which the speech recognizer will wait before finalizing the

recognition operation
• The default setting is 150 milliseconds

Customizing Speech Recognition
recoWithUI.Settings.ReadoutEnabled = false; // don't read the saying back
recoWithUI.Settings.ShowConfirmation = false; // don't show the confirmation

recoWithUI.Recognizer.Settings.InitialSilenceTimeout = TimeSpan.FromSeconds(6.0);
recoWithUI.Recognizer.Settings.BabbleTimeout = TimeSpan.FromSeconds(4.0);
recoWithUI.Recognizer.Settings.EndSilenceTimeout = TimeSpan.FromSeconds(1.2);

• A program can also select whether or not the speech recognition echoes back the user
input and displays it in a message box
• The code above also sets timeout values

Handling Errors
recoWithUI.Recognizer.AudioProblemOccurred +=Recognizer_AudioProblemOccurred;
recoWithUI.Recognizer.AudioCaptureStateChanged +=
Recognizer_AudioCaptureStateChanged;
...
void Recognizer_AudioProblemOccurred(SpeechRecognizer sender,
SpeechAudioProblemOccurredEventArgs args)
{
MessageBox.Show("PLease speak more clearly");
}

• An application can bind to events which indicate problems with the audio input
• There is also an event fired when the state of the capture changes

Grammars and Speech input
• The simple speech recognition we have seen so far uses the “Short Dictation” grammar
which just captures the text and returns it to the application
• You can add your own grammars that will structure the conversation between the user and

the application
• Grammars can be created using the Speech Recognition Grammar Specification (SRGS)
Version 1.0 and stored as XML files loaded when the application runs

• This is a little complex, but worth the effort if you want to create applications with rich
language interaction with the user
• If the application just needs to identify particular commands you can use a grammar list to
achieve this
• Custom grammars can be handled on the client without any network access

Using Grammar Lists
string [] strengthNames = { "weak", "mild", "medium", "strong", "english"};
recoWithUI.Recognizer.Grammars.AddGrammarFromList("cheeseStrength",
strengthNames);

• To create a Grammar List an application defines an array of strings that form the words in
the list
• The Grammar can then be added to the recognizer and given a name
• Multiple grammar lists can be added to a grammar recognizer
• The recognizer will now resolve any of the words in the lists that have been supplied

Enabling and Disabling Grammar Lists
recoWithUI.Settings.ListenText = "How strong do you like your cheese?";
recoWithUI.Recognizer.Grammars["cheeseStrength"].Enabled = true;
SpeechRecognitionUIResult recoResult = await recoWithUI.RecognizeWithUIAsync();

• An application can enable or disable particular grammars before a recognition action
• It is also possible to set relative weightings of grammar lists
• The text displayed as part of the listen operation can also be set, as shown above

Determining the confidence in the result
SpeechRecognitionUIResult recoResult = await recoWithUI.RecognizeWithUIAsync();

if ( recoResult.RecognitionResult.TextConfidence ==
SpeechRecognitionConfidence.High )
{
// select cheese based on strength value
}

• An application can determine the confidence that the speech system has in the result that
was obtained
• Result values are High, Medium, Low, Rejected

Matching Multiple Grammars
var alternatives = recoResult.RecognitionResult.GetAlternates(3);

• If the spoken input matches multiple grammars a program can obtain a list of the
alternative results using recoResult.RecognitionResult.GetAlternatives
• The list is supplied in order of confidence
• The application can then determine the best fit from the context of the voice request

• This list is also provided if the request used a more complex grammar

Profanity
• Words that are recognised as profanities are not displayed in the response from a
recognizer command
• The speech system will also not repeat them
• They are enclosed in <Profanity> </Profanity> when supplied to the program that
receives the speech data

Summary
• Applications in Windows Phone 8 can use speech generation and recognition to interact
with users
• Applications can produce speech output from text files which can be marked up with

Speech Synthesis Markup Language (SSML) to include sound files
• Applications can be started and provided with initial commands by registering a Voice
Command Definition File with the Windows Phone

• The commands can be picked up when a page is loaded, or the commands specify a
particular page to load
• An application can modify the phrase part of a command to change the

activation commands
• Applications can recognise speech using complex grammars or simple word lists

45

Summary and Next Steps…
Get Ready to Become a Windows Phone Developer

1

Download the SDK at dev.windowsphone.com

2

Windows Phone 8 Jump Start Training: http://bit.ly/wp8jump

Explore the Microsoft samples and start building apps in Visual Studio
Learn More About Windows Phone Development via Official Microsoft Videos
Windows Phone 8 Dev for Absolute Beginners: http://bit.ly/wp8devAB
Check Out Additional Learning Resources

3

Pluralsight WP Training: www.pluralsight.com/training/Courses#windows-phone
Nokia Developer: www.developer.nokia.com

4

Download Additional Resources & Become an Expert
Download the Windows Phone Toolkit: phone.codeplex.com

Nokia Developer Offers: http://bit.ly/nokiadevoffers

Windows Phone Resources
• Windows Phone Developer Blog: blogs.windows.com/windows_phone/b/wpdev
• Windows Phone Consumer Blog: blogs.windows.com/windows_phone/b/windowsphone

• Nokia WP Wiki: www.developer.nokia.com/Community/Wiki/Category:Windows_Phone
• Nokia Dvlup Challenges & Rewards: www.dvlup.com
• Nokia Conversations Blog: http://conversations.nokia.com
• Microsoft App Studio: http://apps.windowsstore.com
• Nick Landry’s Blog: ActiveNick.net

• Windows Phone Developer Magazine (online): http://flip.it/95YFG
• GeekChamp (WP & Win8 dev): www.geekchamp.com
• Windows Phone Central (News): www.wpcentral.com

Thank You!
Slides and demos will be posted on SlideShare (see links below)
Let me know how you liked this session. Your feedback is important and appreciated.
Blog: www.ActiveNick.net
Twitter: @ActiveNick
Email: activenick@mobility42.com
Mobile Apps: www.bigbaldapps.com
LinkedIn: www.linkedin.com/in/activenick
Website: www.mobility42.com
Slideshare: www.slideshare.net/ActiveNick

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