diff --git a/src/test/java/org/cqfn/astranaut/core/utils/JsonSerializerTest.java b/src/test/java/org/cqfn/astranaut/core/utils/JsonSerializerTest.java
index 537f783..fbc8c73 100644
--- a/src/test/java/org/cqfn/astranaut/core/utils/JsonSerializerTest.java
+++ b/src/test/java/org/cqfn/astranaut/core/utils/JsonSerializerTest.java
@@ -27,17 +27,13 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.List;
 import java.util.Map;
 import org.cqfn.astranaut.core.base.Builder;
-import org.cqfn.astranaut.core.base.ChildDescriptor;
 import org.cqfn.astranaut.core.base.DraftNode;
-import org.cqfn.astranaut.core.base.EmptyFragment;
 import org.cqfn.astranaut.core.base.EmptyTree;
-import org.cqfn.astranaut.core.base.Fragment;
 import org.cqfn.astranaut.core.base.Node;
+import org.cqfn.astranaut.core.base.NodeAndType;
 import org.cqfn.astranaut.core.base.Tree;
-import org.cqfn.astranaut.core.base.Type;
 import org.cqfn.astranaut.core.example.LittleTrees;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -59,6 +55,11 @@ class JsonSerializerTest {
      */
     private static final String TESTS_PATH = "src/test/resources/json/";
 
+    /**
+     * Test node with language.
+     */
+    private static final Node TEST_NODE_LANG = new TestNodeWithTypeWithLanguage();
+
     /**
      * Test for a tree serialization to a JSON string.
      */
@@ -77,7 +78,7 @@ void testSerializationToString() {
      */
     @Test
     void testSerializationWithLanguageSpecified() {
-        final Tree tree = new Tree(new TestNodeWithTypeWithLanguage());
+        final Tree tree = new Tree(JsonSerializerTest.TEST_NODE_LANG);
         final boolean result = this.serializeAndCompare(
             tree,
             "serialization_language_specified.json"
@@ -85,6 +86,22 @@ void testSerializationWithLanguageSpecified() {
         Assertions.assertTrue(result);
     }
 
+    /**
+     * Test for a tree serialization where language is specified.
+     */
+    @Test
+    void testSerializationNestedWithLanguageSpecified() {
+        final DraftNode.Constructor ctor = new DraftNode.Constructor();
+        ctor.setName("Root");
+        ctor.setChildrenList(Collections.singletonList(JsonSerializerTest.TEST_NODE_LANG));
+        final Tree tree = new Tree(ctor.createNode());
+        final boolean result = this.serializeAndCompare(
+            tree,
+            "serialization_nested_language_specified.json"
+        );
+        Assertions.assertTrue(result);
+    }
+
     /**
      * Test for a tree serialization to a JSON string.
      */
@@ -186,65 +203,39 @@ private boolean serializeAndCompare(final Tree tree, final String filename) {
     }
 
     /**
-     * Some type where language is specified.
+     * Some node which has a type where language is specified.
      *
      * @since 1.1.0
      */
-    private static class TestTypeWithLanguage implements Type {
+    private static class TestNodeWithTypeWithLanguage extends NodeAndType {
+
         @Override
         public String getName() {
             return "GandalfTheGrey";
         }
 
         @Override
-        public List<ChildDescriptor> getChildTypes() {
-            return Collections.emptyList();
-        }
-
-        @Override
-        public List<String> getHierarchy() {
-            return Collections.singletonList(this.getName());
+        public String getData() {
+            return "Abracadabra";
         }
 
         @Override
-        public Map<String, String> getProperties() {
-            return new MapUtils<String, String>().put("language", "elven").make();
+        public int getChildCount() {
+            return 0;
         }
 
         @Override
-        public Builder createBuilder() {
+        public Node getChild(final int index) {
             return null;
         }
-    }
-
-    /**
-     * Some node which has a type where language is specified.
-     *
-     * @since 1.1.0
-     */
-    private static class TestNodeWithTypeWithLanguage implements Node {
-        @Override
-        public Fragment getFragment() {
-            return EmptyFragment.INSTANCE;
-        }
-
-        @Override
-        public Type getType() {
-            return new TestTypeWithLanguage();
-        }
-
-        @Override
-        public String getData() {
-            return "Abracadabra";
-        }
 
         @Override
-        public int getChildCount() {
-            return 0;
+        public Map<String, String> getProperties() {
+            return new MapUtils<String, String>().put("language", "elven").make();
         }
 
         @Override
-        public Node getChild(final int index) {
+        public Builder createBuilder() {
             return null;
         }
     }
diff --git a/src/test/resources/json/serialization_nested_language_specified.json b/src/test/resources/json/serialization_nested_language_specified.json
new file mode 100644
index 0000000..cd8df2b
--- /dev/null
+++ b/src/test/resources/json/serialization_nested_language_specified.json
@@ -0,0 +1,12 @@
+{
+  "root": {
+    "type": "Root",
+    "children": [
+      {
+        "type": "GandalfTheGrey",
+        "data": "Abracadabra"
+      }
+    ]
+  },
+  "language": "elven"
+}
\ No newline at end of file