Laravel localization for multi-language apps

<?php

return [
    'welcome' => '¡Bienvenido a nuestra aplicación!',
    'greeting' => 'Hola, :name',
    'posts' => [
        'created' => 'Publicación creada exitosamente',
        'updated' => 'Publicación actualizada exitosamente',
        'deleted' => 'Publicación eliminada exitosamente',
    ],
    'items_count' => '{0} Sin artículos|{1} Un artículo|[2,*] :count artículos',
    'time_ago' => 'hace :time',
];

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\App;

class SetLocale
{
    public function handle(Request $request, Closure $next)
    {
        // Check URL parameter
        if ($request->has('lang')) {
            $locale = $request->get('lang');
            session(['locale' => $locale]);
        }

        // Get from session or user preference
        $locale = session('locale')
            ?? $request->user()?->locale
            ?? config('app.locale');

        // Validate locale
        if (in_array($locale, config('app.available_locales'))) {
            App::setLocale($locale);
        }

        return $next($request);
    }
}

<?php

// Simple translation
echo __('messages.welcome');

// With parameters
echo __('messages.greeting', ['name' => 'Carlos']);

// Nested keys
echo __('messages.posts.created');

// Pluralization
echo trans_choice('messages.items_count', 0); // "No items"
echo trans_choice('messages.items_count', 1); // "One item"
echo trans_choice('messages.items_count', 5); // "5 items"

// In Blade
@lang('messages.welcome')
{{ __('messages.greeting', ['name' => $user->name]) }}

// JSON translations
echo __('This is a simple string');

// Change locale
App::setLocale('es');

// Get current locale
$locale = App::getLocale();

// Carbon localization
$date = now()->locale('es')->diffForHumans(); // "hace 2 horas"