set all locales if app locale changes

app__Http__Middleware__Localized.php

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;

class Localized
{
    /**
     * @param Request $request
     * @param Closure $next
     *
     * @return RedirectResponse|mixed
     */
    public function handle(Request $request, Closure $next)
    {
        $locale = $request->route('language');

        if (! in_array($locale, config('app.locales'))) {
          // do something if the locale is unknown `app.locales` is a custom config value
        }

        app()->setLocale($locale);

        return $next($request);
    }
}

app__Listeners__SetAppLocale.php

<?php

namespace App\Listeners;

use Carbon\Carbon;
use Illuminate\Foundation\Events\LocaleUpdated;
use Illuminate\Support\Facades\URL;

class SetAppLocale
{
    public function handle(LocaleUpdated $event): void
    {
        setlocale(LC_ALL, $event->locale);

        URL::defaults([
            'language' => $event->locale,
        ]);

        Carbon::setLocale($event->locale);
    }
}

app__Providers__EventServiceProvider.php

<?php

namespace App\Providers;

use App\Listeners\SetAppLocale;
use Illuminate\Foundation\Events\LocaleUpdated;
use Illuminate\Foundation\Support\Providers\EventServiceProvider as ServiceProvider;

class EventServiceProvider extends ServiceProvider
{
    protected $listen = [
        LocaleUpdated::class => [
            SetAppLocale::class,
        ],
    ];
}

routes__web.php

<?php

Route::group([
    'middleware' => ['localized'],
    'prefix' => '{language}',
], function (): void {
    // your localized routes
});