Speech Recognition in Uno

[!TIP] 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 WinUI 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

Requirement

iOS

iOS 10 or later is required.

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

xml

<key>NSSpeechRecognitionUsageDescription</key>  
<string>[SpeechRecognition usage description]</string>  
<key>NSMicrophoneUsageDescription</key>  
<string>[SpeechRecognition usage description]</string>

Android

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

xml

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

Limitation

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