Call SetLocale on first visit to the site?

Question

Laravel

Now I have a middleware that changes the language on the site

public function handle($request, Closure $next)
    {
        $locale = $request->segment(1);

        if (!in_array($request->segment(1), config('app.available_locales'))) {
            $locale = config('app.locale');
        }

        app()->setLocale($locale);

        return $next($request);
    }

And here is the routing

Route::get('/', function () {
    return redirect(app()->getLocale());
});

Route::group([
    'prefix' => '{locale}',
    'where'  => ['locale' => '[a-zA-Z]{2}'],
    'middleware' => 'setlocale'
], function () {
...
});

How to make it so that when you first enter the site, not the default language is set, but some other?