下面是API類
Asr.cs

using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

/// <summary>
/// 用戶解析token的json數據
/// </summary>
class TokenResponse
{
    public string access_token = null;
}

public class Asr
{
    public string SecretKey { get; private
 
 set; }

    public string APIKey { get; private set; }
    public string Token { get; private set; }

    public Asr(string apiKey, string secretKey)
    {
        APIKey = apiKey;
        SecretKey = secretKey;
    }

    public IEnumerator GetAccessToken()
    {
        var uri =
            string
 
.Format(
                "https://openapi.baidu.com/oauth/2.0/token?grant_type=client_credentials&client_id={0}&client_secret={1}",
                APIKey, SecretKey);
        var www = new WWW(uri);
        yield return www;

        if (string.IsNullOrEmpty(www.error))
        {
            
 
var result = JsonUtility.FromJson<TokenResponse>(www.text);
            Token = result.access_token;
            Debug.Log("Get access_token successfully");
        }
        else
        {
            Debug.LogError(www.error);
        }
    }

    public IEnumerator Recognize(byte[] data, Action<string> callback)
    {
        var uri =
            string.Format("http://vop.baidu.com/server_api?lan=zh&cuid={0}&token={1}",
                SystemInfo.deviceUniqueIdentifier, Token);

        var headers = new Dictionary<string, string> { { "Content-Type", "audio/pcm;rate=16000" } };

        var www = new WWW(uri, data, headers);
        yield return www;
        if (string.IsNullOrEmpty(www.error))
        {
            Debug.Log(www.text);

            callback(www.text);
        }
        else
            Debug.LogError(www.error);
    }

    /// <summary>
    /// 將Unity的AudioClip數據轉化為PCM格式16bit數據
    /// </summary>
    /// <param name="clip"></param>
    /// <returns></returns>
    public static byte[] ConvertAudioClipToPCM16(AudioClip clip)
    {
        var samples = new float[clip.samples * clip.channels];
        clip.GetData(samples, 0);
        var samples_int16 = new short[samples.Length];

        for (var index = 0; index < samples.Length; index++)
        {
            var f = samples[index];
            samples_int16[index] = (short)(f * short.MaxValue);
        }

        var byteArray = new byte[samples_int16.Length * 2];
        Buffer.BlockCopy(samples_int16, 0, byteArray, 0, byteArray.Length);

        return byteArray;
    }
}

下面是測試類

main.cs

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class main : MonoBehaviour {

    public string APIKey = "";
    public string SecretKey = "";
    public Button StartButton;
    public Button StopButton;
    public Text DescriptionText;

    private AudioClip _clipRecord = new AudioClip();
    private Asr _asr;

    void Start()
    {
        _asr = new Asr(APIKey, SecretKey);
        StartCoroutine(_asr.GetAccessToken());

        StartButton.gameObject.SetActive(true);
        StopButton.gameObject.SetActive(false);
        DescriptionText.text = "";

        StartButton.onClick.AddListener(OnClickStartButton);
        StopButton.onClick.AddListener(OnClickStopButton);
    }

    private void OnClickStartButton()
    {
        StartButton.gameObject.SetActive(false);
        StopButton.gameObject.SetActive(true);
        DescriptionText.text = "Listening...";

        _clipRecord = Microphone.Start(null, false, 30, 16000);
    }

    private void OnClickStopButton()
    {
        StartButton.gameObject.SetActive(false);
        StopButton.gameObject.SetActive(false);
        DescriptionText.text = "Recognizing...";
        Microphone.End(null);
        Debug.Log("end record");
        var data = Asr.ConvertAudioClipToPCM16(_clipRecord);
        StartCoroutine(_asr.Recognize(data, s =>
        {

            DescriptionText.text = s;
            StartButton.gameObject.SetActive(true);
        }));

    }
}

資源來源於關爾Manic的技術園

http://blog.csdn.net/zhenghongzhi6/article/details/78688571#comments

Unity中使用百度中文語音識別功能