Specify the speech recognizer language
Learn how to select an installed language to use for speech recognition.
Here, we enumerate the languages installed on a system, identify which is the default language, and select a different language for recognition.
This topic builds on Speech recognition.
You should have a basic understanding of speech recognition and recognition constraints.
If you're new to developing Universal Windows Platform (UWP) apps, have a look through these topics to get familiar with the technologies discussed here.
User experience guidelines:
For helpful tips about designing a useful and engaging speech-enabled app, see Speech design guidelines .
Identify the default language
A speech recognizer uses the system speech language as its default recognition language. This language is set by the user on the device Settings > System > Speech > Speech Language screen.
We identify the default language by checking the SystemSpeechLanguage static property.
var language = SpeechRecognizer.SystemSpeechLanguage;
Confirm an installed language
Installed languages can vary between devices. You should verify the existence of a language if you depend on it for a particular constraint.
Note A reboot is required after a new language pack is installed. An exception with error code SPERR_NOT_FOUND (0x8004503a) is raised if the specified language is not supported or has not finished installing.
Determine the supported languages on a device by checking one of two static properties of the SpeechRecognizer class:
Specify a language
Here, we specify "en-US" as the recognition language.
var language = new Windows.Globalization.Language(“en-US”); var recognizer = new SpeechRecognizer(language);
A topic constraint can be configured by adding a SpeechRecognitionTopicConstraint to the Constraints collection of the SpeechRecognizer and then calling CompileConstraintsAsync. A SpeechRecognitionResultStatus of TopicLanguageNotSupported is returned if the recognizer is not initialized with a supported topic language.
A list constraint is configured by adding a SpeechRecognitionListConstraint to the Constraints collection of the SpeechRecognizer and then calling CompileConstraintsAsync. You cannot specify the language of a custom list directly. Instead, the list will be processed using the language of the recognizer.
An SRGS grammar is an open-standard XML format represented by the SpeechRecognitionGrammarFileConstraint class. Unlike custom lists, you can specify the language of the grammar in the SRGS markup. CompileConstraintsAsync fails with a SpeechRecognitionResultStatus of TopicLanguageNotSupported if the recognizer is not initialized to the same language as the SRGS markup.