Speech Recognition in Uno


This article covers Uno-specific information for Windows.Media.SpeechRecognition. For a full description of the feature and instructions on using it, see SpeechRecognition Namespace.

  • The Windows.Media.SpeechRecognition class allows an application to recognize voice input.

Uno's implementation currently supports basic native speech recognition.

Supported Features

The following features of Windows.Media.SpeechRecognition.SpeechRecognizer are currently supported:

Feature iOS Android Remarks
SpeechRecognizer() X X
SpeechRecognizer(Language) X X
Constraints - -
ContinuousRecognitionSession - -
CurrentLanguage X X
State X X
SupportedGrammarLanguages - -
SupportedTopicLanguages - -
SystemSpeechLanguage - -
Timeouts X X
UIOptions X X Not used
CompileConstraintsAsync() X X Always return Success (implemented to meet UWP constraint that requires CompileConstraintsAsync() to be called before RecognizeAsync())
Dispose() X X
RecognizeAsync() X X
RecognizeWithUIAsync() - -
StopRecognitionAsync()() X X
TrySetSystemSpeechLanguageAsync(Language) - -
HypothesisGenerated X X
RecognitionQualityDegrading - -
StateChanged X X



  • iOS 10 or later is required.

  • The following lines need to be added to your info.plist:

    <string>[SpeechRecognition usage description]</string>  
    <string>[SpeechRecognition usage description]</string> 


The following lines need to be added to your AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />


In Windows.Media.SpeechRecognition.SpeechRecognitionResult, only Text, Alternates, and GetAlternates(uint maxAlternates) are implemented. In particular, RawConfidence and Confidence fields are not currently supported.