Web Speech API Grammar 是否向开发人员公开？

我目前正在对 Webkit 语音识别进行一些研究，我想创建一个特定于应用程序的语法文件。 根据W3C的定义我写了下面的代码。但它似乎并没有显示出对这些单词的识别效果有所改善。您能提供一些帮助吗？

var 识别 = new webkitSpeechRecognition(); recognize.grammars.addFromUri("voice/api_grammar/weight.grxml");

语法文件是一个简单的文件，如下所示。

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE grammar PUBLIC "-//W3C//DTD GRAMMAR 1.0//EN"
                  "http://www.w3.org/TR/speech-grammar/grammar.dtd">

<grammar version="1.0"
         xmlns="http://www.w3.org/2001/06/grammar"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:schemaLocation="http://www.w3.org/2001/06/grammar 
                             http://www.w3.org/TR/speech-grammar/grammar.xsd"
         xml:lang="en-US" mode="voice" root="sequence">

  <meta name='description' content='Example using examples'/>

  <meta name='in.1' content='sunny Yorktown Heights New York United States'/>
  <meta name='out.1' content='$sequence[$repeat[$alternatives["sunny"]],$ruleref[$token["Yorktown Heights"]],$Token["New","York"],$TOKEN["United States"]]'/>




  <rule id="ruleref">
    <example>"Yorktown Heights"</example>
    <ruleref uri="#token"/>
  </rule>

  <rule id="alternatives">
    <example>sunny</example>
    <example>cloudy</example>
    <example>warm</example>
    <example>cold</example>
    <one-of>
      <item> sunny </item>
      <item> cloudy </item>
      <item> warm </item>
      <item> cold </item>
    </one-of>
  </rule>

  <rule id="repeat">
   <example></example> <!-- for count=0 -->
   <example>warm</example>
   <example>warm sunny cloudy</example>
   <item repeat="0-3">
      <ruleref uri="#alternatives"/>
   </item>
  </rule>

  <rule id="sequence">
    <example>
      warm sunny cloudy "Yorktown Heights" New York "United States"
    </example>
    <example>
      warm sunny cloudy   Yorktown   Heights   New York United
            States
    </example>
    <example> <!-- this example is actually wrong but that is legal -->
      warm sunny cloudy "Yorktown   Heights" New York "United States"
    </example>

    <ruleref uri="#repeat"/> <ruleref uri="#ruleref"/>
    <ruleref uri="#Token"/> <ruleref uri="#TOKEN"/>    
  </rule>

</grammar>

虽然 w3c 指定了网络语音的语法，但 google chrome 尚未实现。