Как вывести из дополнительного слова по первой букве алфавита?

if( ! defined( 'DATALIFEENGINE' ) ) { die( "Hacking attempt!" ); }

$xflist = dle_cache( $xfname, $config['skin'] );
if(!$xflist) {
	$sql_result = $db->query( "SELECT xfields FROM " . PREFIX . "_post WHERE approve=1" );
	while ( $rows = $db->get_row( $sql_result ) ) {
		$xfields[] = $rows;
	}	
	$stack = array();
	foreach($xfields as $value){
		if($value[xfields]){
			$row = xfieldsdataload($value[xfields]);
			if($row[$xfname]){
				$rowdata = explode( "~", $row[$xfname]);
				foreach($rowdata as $value){
					if($value){
						$value = trim($value);
						array_unshift($stack, $value);
					}
				}
			}
		}
	}
	$stack = array_unique($stack);
	sort ($stack);	
	foreach( $stack as $value ){
		$xflist .= "<li><a href='/xfsearch/" . $value . "'>" . $value . "</a></li>\n";
	}
	create_cache( $xfname, $xflist, $config['skin'] );
}
echo "<ul>" . $xflist . "</ul>";