อยากสอบถาม Code PHP โหลดไฟล์ MP3 จาก Google translate API ครับ

<?php

// Convert Words (text) to Speech (MP3)
// ------------------------------------

// Google Translate API cannot handle strings > 100 characters
   $words = substr($_GET['words'], 0, 100);

// Replace the non-alphanumeric characters 
// The spaces in the sentence are replaced with the Plus symbol
   $words = urlencode($_GET['words']);

// Name of the MP3 file generated using the MD5 hash
   $file  = md5($words);
  
// Save the MP3 file in this folder with the .mp3 extension 
   $file = "audio/" . $words . ".mp3";

// If the MP3 file exists, do not create a new request
   if (!file_exists($file)) {
     $mp3 = file_get_contents('http://translate.google.com/translate_tts?q=' . $words);
     file_put_contents($file, $mp3);
   }
   echo $mp3."<br>".$words."<br>".$file."<br>";
?>

// Embed the MP3 file using the AUDIO tag of HTML5 </BR>
<audio controls="controls" autoplay="autoplay">
  <source src="<?php echo $mp3; ?>" type="audio/mp3" />
</audio>