diff --git a/src/AutoTranslate.php b/src/AutoTranslate.php
index 6b9c3e2..df5b31a 100644
--- a/src/AutoTranslate.php
+++ b/src/AutoTranslate.php
@@ -84,7 +84,7 @@ public function fillLanguageFiles(string $language, array $data)
     public function array_undot(array $dottedArray, array $initialArray = []) : array
     {
         foreach ($dottedArray as $key => $value) {
-            array_set($initialArray, $key, $value);
+            Arr::set($initialArray, $key, $value);
         }
 
         return $initialArray;
diff --git a/src/Commands/AllCommand.php b/src/Commands/AllCommand.php
index 687d340..c26c5b1 100644
--- a/src/Commands/AllCommand.php
+++ b/src/Commands/AllCommand.php
@@ -44,14 +44,23 @@ public function handle()
     {
         $targetLanguages = Arr::wrap(config('auto-translate.target_language'));
 
+        $this->line('Found '.count($targetLanguages).' languages to translate');
+
+        $bar = $this->output->createProgressBar(count($targetLanguages));
+        $bar->start();
+
         foreach ($targetLanguages as $targetLanguage) {
             $sourceTranslations = $this->autoTranslator->getSourceTranslations();
 
             $translated = $this->autoTranslator->translate($targetLanguage, $sourceTranslations);
 
             $this->autoTranslator->fillLanguageFiles($targetLanguage, $translated);
+
+            $bar->advance();
         }
 
+        $bar->finish();
+
         $this->info('Translated '.count(Arr::dot($sourceTranslations)).' language keys.');
     }
 }
diff --git a/src/Commands/MissingCommand.php b/src/Commands/MissingCommand.php
index 57bcba4..1455786 100644
--- a/src/Commands/MissingCommand.php
+++ b/src/Commands/MissingCommand.php
@@ -44,6 +44,11 @@ public function handle()
     {
         $targetLanguages = Arr::wrap(config('auto-translate.target_language'));
 
+        $this->line('Found '.count($targetLanguages).' languages to translate');
+
+        $bar = $this->output->createProgressBar(count($targetLanguages));
+        $bar->start();
+
         $missingCount = 0;
 
         foreach ($targetLanguages as $targetLanguage) {
@@ -53,8 +58,12 @@ public function handle()
             $translated = $this->autoTranslator->translate($targetLanguage, $missing);
 
             $this->autoTranslator->fillLanguageFiles($targetLanguage, $translated);
+
+            $bar->advance();
         }
 
+        $bar->finish();
+
         $this->info('Translated '.$missingCount.' missing language keys.');
     }
 }
diff --git a/src/Exceptions/LanguageCodeNotExist.php b/src/Exceptions/LanguageCodeNotExist.php
new file mode 100644
index 0000000..58c6e79
--- /dev/null
+++ b/src/Exceptions/LanguageCodeNotExist.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Ben182\AutoTranslate\Exceptions;
+
+use Exception;
+
+class LanguageCodeNotExist extends Exception
+{
+    public static function throw(string $source, string $target): self
+    {
+        return new static('The language code "'.$source.'" or "'.$target.'" does not exist.');
+    }
+}
diff --git a/src/Translators/SimpleGoogleTranslator.php b/src/Translators/SimpleGoogleTranslator.php
index 632f994..1f7048e 100644
--- a/src/Translators/SimpleGoogleTranslator.php
+++ b/src/Translators/SimpleGoogleTranslator.php
@@ -3,10 +3,13 @@
 namespace Ben182\AutoTranslate\Translators;
 
 use Stichoza\GoogleTranslate\GoogleTranslate;
+use Ben182\AutoTranslate\Exceptions\LanguageCodeNotExist;
 
 class SimpleGoogleTranslator implements TranslatorInterface
 {
     protected $translator;
+    protected $source;
+    protected $target;
 
     public function __construct()
     {
@@ -15,6 +18,8 @@ public function __construct()
 
     public function setSource(string $source)
     {
+        $this->source = $source;
+
         $this->translator->setSource($source);
 
         return $this;
@@ -22,6 +27,8 @@ public function setSource(string $source)
 
     public function setTarget(string $target)
     {
+        $this->target = $target;
+
         $this->translator->setTarget($target);
 
         return $this;
@@ -29,6 +36,14 @@ public function setTarget(string $target)
 
     public function translate(string $string) : string
     {
-        return $this->translator->translate($string);
+        try {
+            sleep(random_int(1, 3));
+
+            return $this->translator->translate($string);
+        } catch (\Throwable $th) {
+            if ($th->getMessage() === 'Return value of Stichoza\GoogleTranslate\GoogleTranslate::translate() must be of the type string, null returned') {
+                throw LanguageCodeNotExist::throw($this->source, $this->target);
+            }
+        }
     }
 }
diff --git a/tests/CommandTest.php b/tests/CommandTest.php
deleted file mode 100644
index 20f669a..0000000
--- a/tests/CommandTest.php
+++ /dev/null
@@ -1,59 +0,0 @@
-<?php
-
-namespace Ben182\AutoTranslate\Tests;
-
-use Ben182\AutoTranslate\AutoTranslateFacade;
-use Ben182\AutoTranslate\Commands\AllCommand;
-use Ben182\AutoTranslate\Commands\MissingCommand;
-
-class CommandTest extends TestCase
-{
-    public function test_AllCommand()
-    {
-        $this->createTempFiles([
-            'en' => [
-                'user' => "<?php\n return ['name' => 'Name', 'age' => 'Age'];",
-            ],
-        ]);
-
-        try {
-            (new AllCommand(app('auto-translate')))->handle();
-        } catch (\Throwable $th) {
-        }
-
-        $translations = AutoTranslateFacade::getTranslations('de');
-
-        $this->assertEquals([
-            'user' => [
-                'name' => 'Name',
-                'age' => 'Alter',
-            ],
-        ], $translations);
-    }
-
-    public function test_MissingCommand()
-    {
-        $this->createTempFiles([
-            'en' => [
-                'user' => "<?php\n return ['name' => 'Name', 'age' => 'Age'];",
-            ],
-            'de' => [
-                'user' => "<?php\n return ['name' => 'Name'];",
-            ],
-        ]);
-
-        try {
-            (new MissingCommand(app('auto-translate')))->handle();
-        } catch (\Throwable $th) {
-        }
-
-        $translations = AutoTranslateFacade::getTranslations('de');
-
-        $this->assertEquals([
-            'user' => [
-                'name' => 'Name',
-                'age' => 'Alter',
-            ],
-        ], $translations);
-    }
-}