Query the categories in all langages with Polylang

/*
Plugin Name: Query the categories in all langages with Polylang
*/

add_filter('request', 'pll_cat_request');
function pll_cat_request($request) {
    // default permalinks
    if (isset($request['cat']))
        $cat = $request['cat'];

    // pretty permalinks
    if (isset($request['category_name'])) {
        $cat = get_category_by_slug($request['category_name']);
        $cat = $cat->term_id;
        unset($request['category_name']);
    }

    if (!isset($cat))
        return $request; // end here if the request is not a category

    // get the category in all languages
    global $polylang;
    foreach ($polylang->get_languages_list() as $lang)
        $cats[] = pll_get_term($cat, $lang);

    $request['cat'] = implode(',', $cats);
    return $request;
}