korbn

The solution I found is to always display the products of the default language, whatever the current language is. All the products are therefore to be set in the default language.

add_filter('woocommerce_shortcode_products_query',function($query_args, $atts){
    foreach($query_args['tax_query'] as $key=>$value){
        if($value['taxonomy']=='language'){
            $query_args['tax_query'][$key]['terms'] = DEFAULT_LANGUAGE_ID;
        }
    }
    return $query_args;
}, 10, 2);

Of course, you will have to replace DEFAULT_LANGUAGE_ID by your default language id. You can find it in Polylang languages tab (wp-admin/admin.php?page=mlang), by looking the id in the default language edit page (not sure if I am clear enough). This is a number, not a slug (like “en”).