<?php

add_filter( 'facetwp_index_row', function( $params, $class ) {
    if ( 'post_types' == $params['facet_name'] ) {
        if ( 'Posts' == $params['facet_display_value'] ) {
            $params['facet_display_value'] = 'Posts SPANISH';
        }
    }
    return $params;
}, 10, 2 );