diff --git a/src/Cache/HashTrait.php b/src/Cache/HashTrait.php
index aa6f4a6..79a8d05 100644
--- a/src/Cache/HashTrait.php
+++ b/src/Cache/HashTrait.php
@@ -21,7 +21,7 @@ public function hash($url, $id, array $headers)
         $headerString = "";
         foreach ($headers as $key => $value) {
             if ($key != Headers::HEADER_XFF) {
-                $headerString = $key.$value;
+                $headerString .= $key.$value;
             }
         }
 
@@ -39,11 +39,7 @@ public function hash($url, $id, array $headers)
      */
     public function isCachable($url, $httpMethod)
     {
-        if ($httpMethod === Client::HTTP_GET && $this->isInitialized()) {
-            return true;
-        }
-
-        return false;
+        return $httpMethod === Client::HTTP_GET && $this->isInitialized();
     }
 
     /**
diff --git a/src/Cache/MemcachedCache.php b/src/Cache/MemcachedCache.php
index 06fcb15..a1b7954 100644
--- a/src/Cache/MemcachedCache.php
+++ b/src/Cache/MemcachedCache.php
@@ -88,6 +88,6 @@ public function delete($key)
      */
     public function isInitialized()
     {
-        return $this->cache == null;
+        return $this->cache != null;
     }
 }
diff --git a/tests/Cache/HashTraitTest.php b/tests/Cache/HashTraitTest.php
index a12bc20..39a9413 100644
--- a/tests/Cache/HashTraitTest.php
+++ b/tests/Cache/HashTraitTest.php
@@ -40,6 +40,17 @@ public function testHashHeader()
         $this->assertNotEquals($hash1, $hash2);
     }
 
+    /** @group tttt */
+    public function testHashLanguageHeader()
+    {
+        $mock = $this->getMockForTrait('\Bookboon\Api\Cache\HashTrait');
+
+        $hash1 = $mock->hash('/test', "WHATEVSID", array(Headers::HEADER_LANGUAGE => 'en, de', Headers::HEADER_BRANDING => 'branding-test'));
+        $hash2 = $mock->hash('/test', "WHATEVSID", array(Headers::HEADER_LANGUAGE => 'de, en', Headers::HEADER_BRANDING => 'branding-test'));
+
+        $this->assertNotEquals($hash1, $hash2);
+    }
+
     public function testRequestIsCacheable()
     {
         $mock = $this->getMockForTrait('\Bookboon\Api\Cache\HashTrait');