ช่วยดูสคริปให้หน่อยครับ จะทำให้มันใช้กับภาษาไทยได้ยังไงหรอครับ

<?php

	$handle = @fopen("syns.txt", "r"); // Open file form read.

	$txt_old = $_POST['txt_old'];
	$txt_new = strtolower('. ' . trim($txt_old));

	if ($handle && $txt_old) 
	{
		while (!feof($handle)) // Loop til end of file.
		{
			$line    = fgets($handle); // Read a line.
			$replace = " {" . trim(str_replace(", ", "|", $line)) . "}";
			$syns    = explode(", ", $line);

			foreach($syns as $syn)
			{
				if(strpos($txt_new, ' ' . $syn . ' ') || strpos($txt_new, ' ' . $syn . 's') || strpos($txt_new, ' ' . $syn . '.') ||  strpos($txt_new, ' ' . $syn . ','))
				//if(strpos($txt_new, ' ' . $syn . ' ') )
				{
					$txt_new = str_replace(' ' . $syn, $replace, $txt_new);
					break; 
				}
			}
			
		}

		$txt_new = ucfirst_sentence(trim($txt_new));
		$txt_new = ucfirst_sentence2(trim($txt_new));
		$txt_new = ucfirst_sentence3(trim($txt_new));
		$txt_new = substr($txt_new, 2);

		fclose($handle); // Close the file.
	}

	function ucfirst_sentence($str)
	{
		//return preg_replace('/\b(\w)/e', 'strtoupper("$0")', $str);
		return preg_replace('/\.\s\b(\w)/e', 'strtoupper("$0")', $str);
	}
	
	function ucfirst_sentence2($str)
	{
		//return preg_replace('/({|\|)\b(\w)/e', 'strtoupper("$0")', $str);
		//return preg_replace('/(\.\s{\b\w)|(\.\s{\b\w\|\w)/e', 'strtoupper("$0")', $str);
		return preg_replace('/\.\s{(\w+\|){0,}./e', 'strtoupper("$0")', $str);
		//return preg_replace('/(\.\s{\b\w)|({(\w)\|\b(\w))/e', 'strtoupper("$0")', $str);
	} 

	function ucfirst_sentence3($str)
	{
		//return preg_replace('/(({|\|)[A-Z]){0}[A-Z]{2,}/e', 'strtolower("$0")', $str);
		return preg_replace('/[A-Z]{2,}/e', 'ucfirst(strtolower("$0"))', $str);
	}

	

?>

<form method=post action="">
	
	<textarea name="txt_old" rows="10" cols="100">
		<?= trim($txt_old); ?>
	</textarea>
	<input type="submit"> <input type="reset">

	<div>
		<?= $txt_new; ?>
	</div>

</form>