This code-sample includes add Text to speech. This sample can be used for many purpose. For example, you can create an captcha speech.

Here is the code
  1. <body>
  2. <form id="form1" runat="server">
  3. <div>
  5. <asp:TextBox ID="txtWord" runat="server"/>
  6. <asp:Button ID="btnSubmit" runat="server" Text="Speack Word" OnClick="btnSubmit_Click"/>
  7. </div>
  8. </form>
  9. </body>
Need to add this library file on code behind
  1. using SpeechLib;
Wirte C# code in the Button_Click event.
  1. protected void btnSubmit_Click(object sender, EventArgs e)
  2. {
  3. //Create Voice Object
  4. //Add text for speach
  5. SpVoice voice = new SpVoice();
  6. voice.Speak(txtWord.Text);
  7. }
Build the application and you can hear the voice.