How to read text from a Wav file using NAudio?

Question

I have a .wav file which contains the text "hello".

The objective is to read the .wav file and to get the text back. I am using NAudio for this purpose by using the below piece of code

using (WaveFileReader reader = new WaveFileReader("D:\\test.wav"))
{                
   byte[] buffer = new byte[reader.Length];
   int read = reader.Read(buffer, 0, buffer.Length);
   short[] sampleBuffer = new short[read / 2];
   System.Buffer.BlockCopy(buffer, 0, sampleBuffer, 0, read);
}

And while converting the array back to string, I am receiving blank text

var bytes = a.SelectMany(x => BitConverter.GetBytes(x)).ToArray();
var originalText = System.Text.Encoding.Unicode.GetString(bytes);

What is that I am missing?

I'm voting to close this question as off-topic because it requires understanding of speech/text recognition process — Roman R., Dec 25 '15 at 08:45
What do you mean by "contains" text "hello"? There are 5 chars/bytes in the audio file which forms the pattern "hello"? Somebody says "hello" and you want to extract it? — Ian, Dec 28 '15 at 16:31
Please specify what you want to do - as already asked by Ian, is there the word "hello" in some encoding (UTF-8 or something else) stored in the file (and if so - why the hell would it have the ending .wav) or is there a sound that sounds like "hello" and you want to recognize the speech of that "sound"? — Markus Safar, Jan 02 '16 at 01:58
Respected Seniors, I actually tried to close this because as rightly told by @ Roman R, I should first understand "speech/text recognition process". But I could not do that since by that time I have already created the bounty. If there is any way to do so (close this question), please do that on my behalf. First I myself will try, and then if i have the doubt I will surely ask. Because asking something on the air regarding which I seriously don't know anything , won't help me in the long run. But thanks to all of you. — priyanka.sarkar, Jan 02 '16 at 17:16
@priyanka.sarkar I see, so what you want is to extract the speech-word "hello" in your recorded ".wav" file. That is rather tough. — Ian, Jan 03 '16 at 04:51

score 1 · Answer 1 · answered Jan 03 '16 at 20:26

Now that you have clarified your question (including what's in the comments), it is a valid question and has an answer!

Microsoft Speech Platform Use WAV File Input for Speech Recognition

The example on that page shows using the API to input a WAV file and output text like so:

The following are the contents of the grammar FlightDestination.grxml.

<?xml version="1.0" encoding="utf-8"?>
<grammar version="1.0" xml:lang="en-US" mode="voice" root="destination" xmlns="http://www.w3.org/2001/06/grammar" tag-format="semantics/1.0">
  <rule id="destination"> 
    <item> I want to fly to </item>
    <ruleref uri="#city"/> 
  </rule>

  <rule id="city">
    <one-of>
      <item> Boston </item>
      <item> Madrid </item>
      <item> London </item>
    </one-of>
  </rule>
</grammar>

This appears to be exactly what you are looking for.