captcha-module/translations/en/oecaptcha_en_lang.php

<?php
/**

 *
 * @category      module
 * @package       captcha
 * @author        OXID eSales AG
 * @link          http://www.oxid-esales.com/
 * @copyright (C) OXID eSales AG 2003-20162016
 */

$sLangName = 'English';

$aLang = array(
    'charset'                         => 'UTF-8',
    'MESSAGE_WRONG_VERIFICATION_CODE' => "The verification code you entered is not correct. Please try again."
);