At least one grammar must be loaded before doing a recognition.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Speech.Recognition;

namespace Voice_Recognition
{
    public partial class Form1 : Form
    {
        SpeechRecognitionEngine recEngine = new SpeechRecognitionEngine();

        public Form1()
        {
            InitializeComponent();
        }

        private void btnEnable_Click(object sender, EventArgs e)
        {
            recEngine.RecognizeAsync(RecognizeMode.Multiple);
            btnDisable.Enabled = true; 
        }
            private void Form1_Load(object sender, EventArgs e)
            {

            Choices commands = new Choices();
            string[] phrases = new string[] {
            "test", "chicken"
            };
            Choices choiceSet = new Choices(phrases);
            GrammarBuilder grammarBuilder = new GrammarBuilder(choiceSet);
            GrammarBuilder gBuilder = new GrammarBuilder();
            gBuilder.Append(commands);
            Grammar grammar = new Grammar(gBuilder);

            recEngine.LoadGrammarAsync(grammar);
            recEngine.SetInputToDefaultAudioDevice();
            recEngine.SpeechRecognized += RecEngine_SpeechRecognized;
            }

        private void RecEngine_SpeechRecognized(object sender, SpeechRecognizedEventArgs e)
        {
            switch (e.Result.Text)
            {
                case "balance breaker":
                    MessageBox.Show("Welsh Dragon, Balance Breaker");
                    break;
                case "balance break":
                    richTextBox1.Text += "\nBalance Break";
                    break;
            }
        }

        private void btnDisable_Click(object sender, EventArgs e)
        {
            recEngine.RecognizeAsyncStop();
            btnDisable.Enabled = false;
        }
    }
}