Speech recognition in Spanish with C#

I have the following code to recognize voice in Spanish, the problem is that there are several words which it does not recognize correctly.

using System;
using System.Speech.Recognition;

namespace SpeechRecognitionApp
{
    class Program
    {
        static void Main(string[] args)
        {

            using (
            SpeechRecognitionEngine recognizer =
              new SpeechRecognitionEngine(
                new System.Globalization.CultureInfo("es-ES")))
            {

                recognizer.LoadGrammar(new DictationGrammar());

                recognizer.SpeechRecognized +=
                  new EventHandler<SpeechRecognizedEventArgs>(recognizer_SpeechRecognized);

                recognizer.SetInputToDefaultAudioDevice();

                recognizer.RecognizeAsync(RecognizeMode.Multiple);

                while (true)
                {
                    Console.ReadLine();
                }
            }
        }

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

I have also tried to define the words that it can recognize, in this way it is never wrong, the drawback is that the number of words that it recognizes is limited to the number of words that I define.

Choices colors = new Choices();
                colors.Add(new string[] { "azul", "rojo", "verde" });

                      // Create a GrammarBuilder object and append the Choices object.
                      GrammarBuilder gb = new GrammarBuilder();
                gb.Append(colors);

                      // Create the Grammar instance and load it into the speech recognition engine.
                      Grammar g = new Grammar(gb);


                // Create and load a dictation grammar.
                recognizer.LoadGrammar(g);

Is there a way to recognize multiple words without getting it wrong and without being limited by the defined words?