I want to add new speech and text.

I tried the codes you have given but could not get a good result.'Speech detected' is always on LABEL

The application doesnnt have a new word  and its grammer addition property.(I think) How can i do  it? Thanks for your help

First, you have to download the speech SDK 5.1 until this thread. The SAPI engine might not be installed on your system so you can donwload it from this
http://www.microsoft.com/downloads/details.aspx?FamilyID=5e86ec97-40a7-453f-b0ee-6583171b4530&DisplayLang=en

then include the

using System.Speech.Recognition;

And try this code, personaly I tried this but experience doesn't give optimal results, I don't know

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        SpeechRecognizer recognizer;
        public Form1()
        {
            InitializeComponent();
            recognizer = new SpeechRecognizer();
            recognizer.SpeechDetected+=new EventHandler(recognizer_SpeechDetected);
            recognizer.SpeechRecognized +=new EventHandler(recognizer_SpeechRecognized);
        }

        private void recognizer_SpeechDetected(object sender, EventArgs e)
        {
            label2.Text = "Speach detected";

        }
        private void recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            label1.Text = e.Result.Text;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            var choises = new Choices();
            for (var i = 0; i <= 100; i++)
                choises.Add(i.ToString());
            GrammarBuilder grammarBuilder = new GrammarBuilder(choises);
            Grammar grammar = new Grammar(grammarBuilder);
            recognizer.LoadGrammar(grammar);
            recognizer.Enabled = true;
        }
    }
}

This is another speech Lib

http://www.easyfreeware.com/speech_engine_dll_sdk-2739-freeware.html

I personaly don't try it, so try it and tell me