kernel.php

<?php

// Add the LanguageMiddleware to $middlewareGroups
// Add it below StartSession Middleware.
protected $middlewareGroups = [
    'web' => [
        \App\Http\Middleware\EncryptCookies::class,
        \Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
        \Illuminate\Session\Middleware\StartSession::class,
        \App\Http\Middleware\LanguageMiddleware::class, // Here's our LanguageMiddleware
        \Illuminate\View\Middleware\ShareErrorsFromSession::class,
        \App\Http\Middleware\VerifyCsrfToken::class,
    ],
];

// OR

// If you don't use the "web" middleware make a new one
protected $middlewareGroups = [
    'web' => [],
    // ...
    // add this to the bottom of $middlewareGroups
    'language' => [
        \Illuminate\Session\Middleware\StartSession::class, // We need sessions for the LanguageMiddleware to work
        \App\Http\Middleware\LanguageMiddleware::class, // Here's our LanguageMiddleware
    ]
];

// PS! Don't use multiple $middlewareGroups in kernel.. lol

LanguageController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

use App\Http\Requests;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Session;

// Caching is useful if we actually use an API to request the locale to use for an IP
use Cache;

class LanguageController extends Controller
{
    // This function will be used in Routes.php
    // It changes the Locale in the session
    public function switchLang($lang)
    {
        // Check if valid language
        if (in_array($lang, ['en', 'ee', 'ru'])) {
            
            Session::set('applocale', $lang);
            
        }
        return redirect()->back();
    }

    public function queryAPI($ip)
    {
    	// Here It's possible to make a request to an IP Geo API to set the user's language.
    	// When using an API I recommend caching the response for that IP.
    	// I just return English by default.
    	return 'en';
    }
    
}

LanguageMiddleware.php

<?php

namespace App\Http\Middleware;

use Closure;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Facades\Session;
use App\Http\Controllers\LanguageController;

class LanguageMiddleware
{
    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if(Session::has('applocale') and in_array(Session::get('applocale'), ['en', 'ee', 'ru'])) {
            
            App::setLocale(Session::get('applocale'));
            
        } else {
            
            $langCtrl = new LanguageController;
            $userIP = request()->ip();

            $userLang = $langCtrl->queryAPI($userIP);

            Session::set('applocale', $userLang);

            App::setLocale($userLang);
            
        }

        return $next($request);
    }
}

routes.php

<?php

// This switches the language
// You need to put this route in 'web' middleware group or your custom one
// I'm going to use the language middleware group since I made one in Kernel.php

Route::group(['middleware' => ['language']], function() {
    Route::get('lang/{lang}', ['as' => 'lang.switch', 'uses' => 'LanguageController@switchLang']);
    
    // Every other Route needs to be here aswell. Since sessions need to be used in all routes!
    // Or atleast every route that needs the locale :)
});