protected function i18n($key = NULL, $path = NULL)
	{
		static $RECAPTCHA_LANG;

		if ( $RECAPTCHA_LANG ) {
			return isset($key) ? $RECAPTCHA_LANG[$key] : $RECAPTCHA_LANG;
		}

		if ( !isset($this->_recaptchaOptions['lang']) ) {
			$language = $this->clientLang();
		} else {
			$language = $this->_recaptchaOptions['lang'];
		}

		$RECAPTCHA_LANG = array(
			'instructions_visual' => 'Enter the words above:',
			'instructions_audio'  => 'Type what you hear:',
			'play_again'          => 'Play sound again',
			'cant_hear_this'      => 'Download sound as MP3',
			'visual_challenge'    => 'Get an image CAPTCHA',
			'audio_challenge'     => 'Get an audio CAPTCHA',
			'refresh_btn'         => 'Get another CAPTCHA',
			'help_btn'            => 'Help',
			'incorrect_try_again' => 'Incorrect, please try again.'
			);

	  	// default: path/to/vendor/lib/ReCaptcha/I18n/recaptcha.lang.[langcode].php
		$path = ( NULL === $path )
			? __DIR__ . DIRECTORY_SEPARATOR . 'I18n'
			: $path;

		$language_file = rtrim($path, '/') . DIRECTORY_SEPARATOR . 'recaptcha.lang.' . $language . '.php';

		if ( file_exists( $language_file  ) ) {

			include_once $language_file;
		}

		return isset($key) ? $RECAPTCHA_LANG[$key] : $RECAPTCHA_LANG;
	}