verbose/lib/getfirstbrowserlang.php

<?php
function getfirstbrowserlang($default='en') {
	if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
		$langs=[];
		$buff=explode(',',$_SERVER['HTTP_ACCEPT_LANGUAGE']);
		foreach ($buff as $ent) {
			$ent=trim($ent);
			$ent=explode(';',$ent);
			(count($ent)<2) ? $ent[1]=1 : $ent[1]=preg_replace('/^q=/','',$ent[1])+0;
			$ent[0]=locale_canonicalize($ent[0]);
			$langs[$ent[0]]=$ent[1];
		}
		arsort($langs);
		$blang=array_key_first($langs);
		return $blang;
	} else {
		return $default;
	}
}
?>