This plugin requires the Windows 7+ SDK.

Provides a Blueprint actor SAPIActor which receives speech recognition events:

void OnSpeechInputStarted();

void OnSpeechInputStopped();

JSON formatted SRGS SML output. You can parse it with VaRest

void OnSpeechRecognized(const FString &SpeechText); // JSON formatted SRGS SML output

void OnSpeechRecognitionError(const FString &ErrorMessage, 
                              const FString &Source, 
                              int32 LineNumber, 
                              const FString &ScriptLine);

Also provides a modal latent action which waits for a response from the user that matches the current grammar:

void GetResponse(FString &ResponseText) // JSON formatted SRGS SML output

Provides the following library functions to manage the recognizer including SRGS grammars

Text to speech:

void Speak(const FString &SpeechText);

Set language (En_US or En_UK):

void SetLanguage(ELanguage Language);

Pause the recognizer:

void PauseSpeechRecognition();

Resume the recognizer:

void ResumeSpeechRecognition();

Enable or disable the specified grammar (file must be relative to the root of your Game directory):

void SetGrammar(const FString &GrammarFile, bool Enabled);

Enable or disable the specified grammar rule, e.g "Grammars/MyGrammar.grxml#Rule1":

void SetRule(const FString &RuleUrl, bool Enabled);

Used in conjunction with GetResponse. Temporarily disables current grammars and enables the specified grammar:

void PushGrammar(const FString &GrammarFile);

Used in conjunction with GetResponse. Enables grammars that were in effect before the last PushGrammar:

void PopGrammar();

Dynamically assign the specified grammar rule:

void AddWordTransition(const FString &RuleUrl, 
                       const TArray<FString> &Words, 
                       bool Overwrite = false, 
                       const FString &WordSeparator = TEXT(";"));

Manually send audio to the recognizer:

void SendAudio(const TArray<uint8> &Samples, int32 Channels, int32 SamplesPerSecond);

Note that you must call SetLanguage and SetGrammar before you will receive any events.