Translate just countdown information (days, hours, minutes, seconds)

if you like to set it for only that element on a default english page -( and not for the whole page)
Setting only the lang attribute for that Element will be not enough.
But you can set for that specific Element the attributes separately – give to the animated countdown element a custom class or like i did a unique ID
f.e.: spanish
then put this to your child-theme functions.php:

function set_spanish_translations(){
?>
<script>
window.addEventListener("DOMContentLoaded", function () { 
  (function($) {       
		$('#spanish').attr('lang', 'es-ES');

		$('#spanish .av-countdown-years .av-countdown-time-label').attr({
		  'data-label': 'Año',
		  'data-label-multi': 'Años'
		});
		$('#spanish .av-countdown-months .av-countdown-time-label').attr({
		  'data-label': 'Mes',
		  'data-label-multi': 'Meses'
		});
		$('#spanish .av-countdown-weeks .av-countdown-time-label').attr({
		  'data-label': 'Semana',
		  'data-label-multi': 'Semanas'
		});
		$('#spanish .av-countdown-days .av-countdown-time-label').attr({
		  'data-label': 'Día',
		  'data-label-multi': 'Días'
		});
		$('#spanish .av-countdown-hours .av-countdown-time-label').attr({
		  'data-label': 'Hora',
		  'data-label-multi': 'Horas'
		});
		$('#spanish .av-countdown-minutes .av-countdown-time-label').attr({
		  'data-label': 'Minuto',
		  'data-label-multi': 'Minutos'
		});
		$('#spanish .av-countdown-seconds .av-countdown-time-label').attr({
		  'data-label': 'Segundo',
		  'data-label-multi': 'Segundos'
		});
  }(jQuery)); 
});
</script>
<?php
}
add_action('wp_footer', 'set_spanish_translations');

see: https://enfold.webers-webdesign.de/3-columns/