SystemSpeechRecognitionExample.cs

using System;
using System.Speech.Recognition;

namespace ConsoleApp
{
    internal static class Program
    {
        private static void Main(string[] args)
        {
            // Create an in-process speech recognizer for the en-US locale.  
            using var recognizer =
                new SpeechRecognitionEngine(
                    new System.Globalization.CultureInfo("en-US")
                );
            // Create and load a dictation grammar.  
            recognizer.LoadGrammar(new DictationGrammar());

            // Add a handler for the speech recognized event.  
            recognizer.SpeechRecognized += recognizer_SpeechRecognized;

            // Configure input to the speech recognizer.  
            recognizer.SetInputToDefaultAudioDevice();

            // Start asynchronous, continuous speech recognition.  
            recognizer.RecognizeAsync(RecognizeMode.Multiple);

            // Keep the console window open.  
            while (true)
            {
                Console.ReadLine();
            }
        }

        // Handle the SpeechRecognized event.  
        static void recognizer_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            Console.WriteLine("Recognized text: " + e.Result.Text);
        }
    }
}