wp-install-locale-language

public function install_locale()
{
	is_admin() or add_filter( 'locale', function($locale) {
		$locale = "ka_GE";
		return $locale;
	});

	//check if it's not install, then install
	add_action('wp', 'my_locale_implemention');
	function my_locale_implemention()
	{
		$my_locale = get_locale();  //get_user_locale
		if ( !empty($my_locale) && !in_array( $my_locale, get_available_languages() ) ) {
			require_once( ABSPATH . 'wp-admin/includes/file.php' );
			require_once( ABSPATH . 'wp-admin/includes/translation-install.php' );
			$language = wp_download_language_pack( $my_locale );
			if ( $language ) {
				if(empty($_POST)) header("location: ".$_SERVER['REQUEST_URI']); exit; //reload page
			}
		}
	}
}