diff --git a/CMakeLists.txt b/CMakeLists.txt
index b999c04..5995819 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@
 # SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #
 cmake_minimum_required(VERSION 3.7)
-project(CycloneDDS VERSION 0.7.0)
+project(CycloneDDS VERSION 0.7.0 LANGUAGES C)
 
 # Set a default build type if none was specified
 set(default_build_type "RelWithDebInfo")
diff --git a/ports/freertos-posix/CMakeLists.txt b/ports/freertos-posix/CMakeLists.txt
index 0c161ce..972e779 100644
--- a/ports/freertos-posix/CMakeLists.txt
+++ b/ports/freertos-posix/CMakeLists.txt
@@ -10,7 +10,7 @@
 # SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 #
 cmake_minimum_required(VERSION 3.5)
-project(FreeRTOS-Sim VERSION 10.0.2.0)
+project(FreeRTOS-Sim VERSION 10.0.2.0 LANGUAGES C)
 
 include(GNUInstallDirs)