PHP: Detect Browser Language

language-detect.php

<?php

/**
 * Gets the user’s browser language, given an array of avalaible languages.
 * @param  array  $availableLanguages avalaible languages for the site
 * @param  string $default            default language for the site
 * @return string                     language prefix
 */
function get_client_language( $availableLanguages, $default='en' ){
	if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {

		$langs = explode(',',$_SERVER['HTTP_ACCEPT_LANGUAGE']);

		foreach ($langs as $value){
			$choice=substr($value,0,2);
			if(in_array($choice, $availableLanguages)){
				return $choice;
			}
		}
	}
	return $default;
}