echo trimmer("The quick brown fox was brown and quick.", 14, false);

function trimmer($message, $K) {
        //trim last word recurisvely and compare to $K
        $pos = strrpos(trim($message) . " ", " ", -2);
        $trimmedString = substr($message, 0, $pos);
        if(strlen($trimmedString) > $K) {
                $trimmedString = trimmer($trimmedString, $K, true);
                return $trimmedString;
        }
}