How to add words to an already loaded grammar using System.Speech and SAPI 5.3

Question

Given the following code,

Choices choices = new Choices();
choices.Add(new GrammarBuilder(new SemanticResultValue("product", "<product/>")));

GrammarBuilder builder = new GrammarBuilder();
builder.Append(new SemanticResultKey("options", choices.ToGrammarBuilder()));

Grammar grammar = new Grammar(builder) { Name = Constants.GrammarNameLanguage};
grammar.Priority = priority;

_recognition.LoadGrammar(grammar);

How can I add additional words to the loaded grammar? I know this can be achieved both in native code and using the SpeechLib interop, but I prefer to use the managed library.

Update: What I want to achieve, is not having to load an entire grammar repeatedly because of individual changes. For small grammars I got good results by calling

_recognition.RequestRecognizerUpdate()

and then doing the unload of the old grammar and loading of a rebuilt grammar in the event:

void Recognition_RecognizerUpdateReached(object sender, RecognizerUpdateReachedEventArgs e)

For large grammars this becomes too expensive.

Answer 1

It sounds like you need to use some indirection, via the a grammar rule reference. This can be done with the GrammarBuilder.AppendRuleReference method. It might be easier to test out your grammars first with some SRGS grammar files.

The principle is that you load a main large grammar which has some references in it, to smaller user specific word lists grammars, which you would dynamically load.

See http://www.w3.org/TR/speech-grammar/#S2.2 for the srgs format, and http://msdn.microsoft.com/en-us/library/system.speech.recognition.grammarbuilder.appendrulereference.aspx for the programmatic version.

Answer 2

An alternative, if you have very large grammars, would be to use the dictation grammar option. There is a standard dictation grammar, but you could also specify your own. See http://msdn.microsoft.com/en-us/library/system.speech.recognition.dictationgrammar.aspx, and it's constructor.

You wouldn't update this. It contains all possible words.

Answer 3

Hi Kim can you send me your above complete code for loading grammar at [email protected]

Actually I am grabbing grammar file from external xml but getting an exception for HRESULT error : 0x80045048

Although my xml rules are according to SAPI documentation.

Answer 4

Hi Kim can you send me above code source because I am unable to add my words and run the code after some modification dynamically.

I want to add words dynamically at runtime to SAPI voice database and also want to add some own training files. Any assistance will be highly appreciated

Answer 5

In native SAPI, I'd use ISpGrammarBuilder2::AddTextSubset().

Answer 6

I know this is an old post.. but has anyone ever reached some conclusion.. or knows of something more? I am dealing with a similar problem.. want to load a generic grammar from a file. This file references external ones ( grammar files ). While the app is running, i wanna be able to add and delete rules depending on situations, thus improving accuracy ( i think)

Any help will be appreciated.