Dictation grammar vs custom grammar

Question

I am working on the following code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Speech.Recognition;
using System.Speech.Synthesis;
using System.Windows.Forms;
using System.IO;

namespace US_Speech_Recognizer
{
    public class RecognizeSpeech
    {
        private SpeechRecognitionEngine sEngine; //Speech recognition engine
        private SpeechSynthesizer sSpeak; //Speech synthesizer
        string text3 = "";

        public RecognizeSpeech()
        {
            //Make the recognizer ready
            sEngine = new SpeechRecognitionEngine(new System.Globalization.CultureInfo("en-US"));


            //Load grammar
            Choices sentences = new Choices();
            sentences.Add(new string[] { "I am hungry" });

            GrammarBuilder gBuilder = new GrammarBuilder(sentences);

            Grammar g = new Grammar(gBuilder);

            sEngine.LoadGrammar(g);

            //Add a handler
            sEngine.SpeechRecognized +=new EventHandler<SpeechRecognizedEventArgs>(sEngine_SpeechRecognized);


            sSpeak = new SpeechSynthesizer();
            sSpeak.Rate = -2;



            //Computer speaks the words to get the phones
            Stream stream = new MemoryStream();
            sSpeak.SetOutputToWaveStream(stream);


            sSpeak.Speak("I was hungry");
            stream.Position = 0;
            sSpeak.SetOutputToNull();


            //Configure the recognizer to stream
            sEngine.SetInputToWaveStream(stream);

            sEngine.RecognizeAsync(RecognizeMode.Single);


        }


        //Start the speech recognition task
        private void sEngine_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            string text = "";

            if (e.Result.Text == "I am hungry")
            {
                foreach (RecognizedWordUnit wordUnit in e.Result.Words)
                {
                    text = text + wordUnit.Pronunciation + "\n";
                }

                MessageBox.Show(e.Result.Text + "\n" + text);
            }


        }
    }
}

In here, the grammar is I am hungry but the computer is asked to speak I was hungry. But the case is, the recognition event get fired and says the text is exact equal to I am hungry. In the output box, you can check the phonemes as well!

The only way to avoid this is loading DictationGrammar

I thought providing custom grammar is the best way to restrict the application from listening to everything not needed, but it seems like custom grammar is failing!

My question is, is there a way to avoid this? Why this is happening?

Answer 1

I found the answer. Custom Grammar will filter the user's pronunciation by giving lot of pressure to the engine to identify the user's voice with the provided LIMITED grammar.

Dictation grammar is not like that, it will simply try to match WHAT COMPUTER UNDERSTOOD rather than what the user exactly said.

This can be minimized by training the speech engine.