$et_error_message how to locate and modify this var

Hi there ppl, my problem is the next one.

url: http://anasanchezterapias.com/contacto/
theme: Fable (from elegant themes)
In my contact page, when you submit (in my case ‘enviar’) with the fields or some of them empty, displays the error messages that the fields are empty and this is good, but i need to tranlate it to Spanish, soooooo i have a bit of a problem researching through the files of wordpress and finding the where is that concats ‘Fill’ with what i pass as a text ‘Nombre’ and ‘field’ concated with my text.

this errors are printed this way:

<div id="et-contact-message"><?php echo($et_error_message); ?> </div>

in the form, the code of the input is like this:

<label for="et_contact_name" class="et_contact_form_label"><?php esc_html_e('Nombre','Fable'); ?></label>
							<input type="text" name="et_contact_name" value="<?php if ( isset($_POST['et_contact_name']) ) echo esc_attr($_POST['et_contact_name']); else esc_attr_e('Nombre','Fable'); ?>" id="et_contact_name" class="input" />

my problem is that i am getting lost, so lost with the researching through the files because the function esc_attr() calls another function in another file and so on and so on.

Say that all this functions don’t have nothing to do with the theme or this is how i saw it because all of them are on the /public_html/wp-includes on various files.

if u need the full code of the contact-page.php i write it next:

<?php if ( ! isset( $_SESSION ) ) session_start();
/*
Template Name: Contact Page
*/
?>
<?php
	$et_ptemplate_settings = array();
	$et_ptemplate_settings = maybe_unserialize( get_post_meta(get_the_ID(),'et_ptemplate_settings',true) );

	$fullwidth = isset( $et_ptemplate_settings['et_fullwidthpage'] ) ? (bool) $et_ptemplate_settings['et_fullwidthpage'] : false;

	$et_regenerate_numbers = isset( $et_ptemplate_settings['et_regenerate_numbers'] ) ? (bool) $et_ptemplate_settings['et_regenerate_numbers'] : false;

	$et_error_message = '';
	$et_contact_error = false;

	if ( isset($_POST['et_contactform_submit']) ) {
		if ( !isset($_POST['et_contact_captcha']) || empty($_POST['et_contact_captcha']) ) {
			$et_error_message .= '<p>' . esc_html__('Entra el captcha. ','Fable') . '</p>';
			$et_contact_error = true;
		} else if ( $_POST['et_contact_captcha'] <> ( $_SESSION['et_first_digit'] + $_SESSION['et_second_digit'] ) ) {
			$et_numbers_string = $et_regenerate_numbers ? esc_html__('Numbers regenerated.','Fable') : '';
			$et_error_message .= '<p>' . esc_html__('Captcha erróneo. ','Fable') . $et_numbers_string . '</p>';

			if ($et_regenerate_numbers) {
				unset( $_SESSION['et_first_digit'] );
				unset( $_SESSION['et_second_digit'] );
			}

			$et_contact_error = true;
		} else if ( empty($_POST['et_contact_name']) || empty($_POST['et_contact_email']) || empty($_POST['et_contact_subject']) || empty($_POST['et_contact_message']) ){
			$et_error_message .= '<p>' . esc_html__('Assegurate de llenar todos los campos. ','Fable') . '</p>';
			$et_contact_error = true;
		}

		if ( !is_email( $_POST['et_contact_email'] ) ) {
			$et_error_message .= '<p>' . esc_html__('Email inválido. ','Fable') . '</p>';
			$et_contact_error = true;
		}
	} else {
		$et_contact_error = true;
		if ( isset($_SESSION['et_first_digit'] ) ) unset( $_SESSION['et_first_digit'] );
		if ( isset($_SESSION['et_second_digit'] ) ) unset( $_SESSION['et_second_digit'] );
	}

	if ( !isset($_SESSION['et_first_digit'] ) ) $_SESSION['et_first_digit'] = $et_first_digit = rand(1, 15);
	else $et_first_digit = $_SESSION['et_first_digit'];

	if ( !isset($_SESSION['et_second_digit'] ) ) $_SESSION['et_second_digit'] = $et_second_digit = rand(1, 15);
	else $et_second_digit = $_SESSION['et_second_digit'];

	if ( ! $et_contact_error && isset( $_POST['_wpnonce-et-contact-form-submitted'] ) && wp_verify_nonce( $_POST['_wpnonce-et-contact-form-submitted'], 'et-contact-form-submit' ) ) {
		$et_email_to = ( isset($et_ptemplate_settings['et_email_to']) && !empty($et_ptemplate_settings['et_email_to']) ) ? $et_ptemplate_settings['et_email_to'] : get_site_option('admin_email');

		$et_site_name = is_multisite() ? $current_site->site_name : get_bloginfo('name');

		$contact_name 	= stripslashes( sanitize_text_field( $_POST['et_contact_name'] ) );
		$contact_email 	= sanitize_email( $_POST['et_contact_email'] );

		$headers  = 'From: ' . $contact_name . ' <' . $contact_email . '>' . "\r\n";
		$headers .= 'Reply-To: ' . $contact_name . ' <' . $contact_email . '>';

		wp_mail( apply_filters( 'et_contact_page_email_to', $et_email_to ), sprintf( '[%s] ' . stripslashes( sanitize_text_field( $_POST['et_contact_subject'] ) ), $et_site_name ), stripslashes( wp_strip_all_tags( $_POST['et_contact_message'] ) ), apply_filters( 'et_contact_page_headers', $headers, $contact_name, $contact_email ) );

		$et_error_message = '<p>' . esc_html__('Gracias por contactar con nosotros','Fable') . '</p>';
	}
?>
<?php get_header(); ?>

<?php while ( have_posts() ) : the_post(); ?>

	<?php get_template_part( 'content', 'page' ); ?>

	<article class="et-additional-content">
		<?php get_template_part( 'includes/breadcrumbs', 'single' ); ?>

		<div class="entry-content container clearfix">
			<?php the_content(); ?>
			<?php wp_link_pages( array( 'before' => '<div class="page-links">' . __( 'Pages:', 'Fable' ), 'after' => '</div>' ) ); ?>

<?php endwhile; ?>

			<div id="et-contact" class="responsive">
				<div id="et-contact-message"><?php echo($et_error_message); ?> </div>

			<?php if ( $et_contact_error ) { ?>
				<form action="<?php echo esc_url( get_permalink( get_the_ID() ) ); ?>" method="post" id="et_contact_form">
					<div id="et_contact_left">
						<p class="clearfix">
							<label for="et_contact_name" class="et_contact_form_label"><?php esc_html_e('Nombre','Fable'); ?></label>
							<input type="text" name="et_contact_name" value="<?php if ( isset($_POST['et_contact_name']) ) echo esc_attr($_POST['et_contact_name']); else esc_attr_e('Nombre','Fable'); ?>" id="et_contact_name" class="input" />
						</p>

						<p class="clearfix">
							<label for="et_contact_email" class="et_contact_form_label"><?php esc_html_e('Dirección electrónica','Fable'); ?></label>
							<input type="text" name="et_contact_email" value="<?php if ( isset($_POST['et_contact_email']) ) echo esc_attr($_POST['et_contact_email']); else esc_attr_e('Dirección electrónica','Fable'); ?>" id="et_contact_email" class="input" />
						</p>

						<p class="clearfix">
							<label for="et_contact_subject" class="et_contact_form_label"><?php esc_html_e('Asunto','Fable'); ?></label>
							<input type="text" name="et_contact_subject" value="<?php if ( isset($_POST['et_contact_subject']) ) echo esc_attr($_POST['et_contact_subject']); else esc_attr_e('Asunto','Fable'); ?>" id="et_contact_subject" class="input" />
						</p>
					</div> <!-- #et_contact_left -->

					<div id="et_contact_right">
						<p class="clearfix">
							<?php
								esc_html_e('Captcha: ','Fable');
								echo '<br/>';
								echo esc_attr($et_first_digit) . ' + ' . esc_attr($et_second_digit) . ' = ';
							?>
							<input type="text" name="et_contact_captcha" value="<?php if ( isset($_POST['et_contact_captcha']) ) echo esc_attr($_POST['et_contact_captcha']); ?>" id="et_contact_captcha" class="input" size="2" />
						</p>
					</div> <!-- #et_contact_right -->

					<div class="clear"></div>

					<p class="clearfix">
						<label for="et_contact_message" class="et_contact_form_label"><?php esc_html_e('Mensaje','Fable'); ?></label>
						<textarea class="input" id="et_contact_message" name="et_contact_message"><?php if ( isset($_POST['et_contact_message']) ) echo esc_textarea($_POST['et_contact_message']); else echo esc_textarea( __('Mensaje','Fable') ); ?></textarea>
					</p>

					<input type="hidden" name="et_contactform_submit" value="et_contact_proccess" />

					<input type="reset" id="et_contact_reset" value="<?php esc_attr_e('Reset','Fable'); ?>" />
					<input class="et_contact_submit" type="submit" value="<?php esc_attr_e('Enviar','Fable'); ?>" id="et_contact_submit" />

					<?php wp_nonce_field( 'et-contact-form-submit', '_wpnonce-et-contact-form-submitted' ); ?>
				</form>
			<?php } ?>
			</div> <!-- end #et-contact -->

		</div> <!-- .entry-content -->
	</article> <!-- .et-additional-content -->

<?php get_footer(); ?>

i appreciate your help and patience here.