diff --git a/lib/pleroma/web/activity_pub/transmogrifier.ex b/lib/pleroma/web/activity_pub/transmogrifier.ex
index f79cb72f8a..79cc79a5b2 100644
--- a/lib/pleroma/web/activity_pub/transmogrifier.ex
+++ b/lib/pleroma/web/activity_pub/transmogrifier.ex
@@ -763,12 +763,11 @@ def prepare_outgoing(%{"type" => activity_type, "object" => object_id} = data)
       object_id
       |> Object.normalize(fetch: false)
       |> Map.get(:data)
-      |> prepare_object
 
     data =
       data
-      |> Map.put("object", object)
-      |> Map.merge(Utils.make_json_ld_header(data))
+      |> Map.put("object", prepare_object(object))
+      |> Map.merge(Utils.make_json_ld_header(object))
       |> Map.delete("bcc")
 
     {:ok, data}
@@ -776,14 +775,10 @@ def prepare_outgoing(%{"type" => activity_type, "object" => object_id} = data)
 
   def prepare_outgoing(%{"type" => "Update", "object" => %{"type" => objtype} = object} = data)
       when objtype in Pleroma.Constants.updatable_object_types() do
-    object =
-      object
-      |> prepare_object
-
     data =
       data
-      |> Map.put("object", object)
-      |> Map.merge(Utils.make_json_ld_header(data))
+      |> Map.put("object", prepare_object(object))
+      |> Map.merge(Utils.make_json_ld_header(object))
       |> Map.delete("bcc")
 
     {:ok, data}
@@ -804,7 +799,7 @@ def prepare_outgoing(%{"type" => "Announce", "actor" => ap_id, "object" => objec
     data =
       data
       |> strip_internal_fields
-      |> Map.merge(Utils.make_json_ld_header(data))
+      |> Map.merge(Utils.make_json_ld_header())
       |> Map.delete("bcc")
 
     {:ok, data}
@@ -824,7 +819,7 @@ def prepare_outgoing(%{"type" => "Accept"} = data) do
       data =
         data
         |> Map.put("object", object)
-        |> Map.merge(Utils.make_json_ld_header(data))
+        |> Map.merge(Utils.make_json_ld_header())
 
       {:ok, data}
     end
@@ -842,7 +837,7 @@ def prepare_outgoing(%{"type" => "Reject"} = data) do
       data =
         data
         |> Map.put("object", object)
-        |> Map.merge(Utils.make_json_ld_header(data))
+        |> Map.merge(Utils.make_json_ld_header())
 
       {:ok, data}
     end
diff --git a/test/pleroma/web/activity_pub/transmogrifier_test.exs b/test/pleroma/web/activity_pub/transmogrifier_test.exs
index 264f0ccdbb..241ed6033a 100644
--- a/test/pleroma/web/activity_pub/transmogrifier_test.exs
+++ b/test/pleroma/web/activity_pub/transmogrifier_test.exs
@@ -374,6 +374,24 @@ test "it prepares a quote post" do
       assert modified["object"]["quoteUrl"] == quote_id
       assert modified["object"]["quoteUri"] == quote_id
     end
+
+    test "it adds language of the object to its json-ld context" do
+      user = insert(:user)
+
+      {:ok, activity} = CommonAPI.post(user, %{status: "Cześć", language: "pl"})
+      {:ok, modified} = Transmogrifier.prepare_outgoing(activity.object.data)
+
+      assert [_, _, %{"@language" => "pl"}] = modified["@context"]
+    end
+
+    test "it adds language of the object to Create activity json-ld context" do
+      user = insert(:user)
+
+      {:ok, activity} = CommonAPI.post(user, %{status: "Cześć", language: "pl"})
+      {:ok, modified} = Transmogrifier.prepare_outgoing(activity.data)
+
+      assert [_, _, %{"@language" => "pl"}] = modified["@context"]
+    end
   end
 
   describe "actor rewriting" do