diff --git a/src/samples/demo/posix/CMakeLists.txt b/src/samples/demo/posix/CMakeLists.txt
index a09a26f9..7f50808b 100644
--- a/src/samples/demo/posix/CMakeLists.txt
+++ b/src/samples/demo/posix/CMakeLists.txt
@@ -5,7 +5,7 @@
 
 cmake_minimum_required(VERSION 3.20.0)
 
-project (ocre_sample_demo)
+project (ocre_sample_demo LANGUAGES C)
 
 add_executable(ocre_demo
     ../main.c
diff --git a/src/samples/mini/posix/CMakeLists.txt b/src/samples/mini/posix/CMakeLists.txt
index 1dee47a5..566ca9e0 100644
--- a/src/samples/mini/posix/CMakeLists.txt
+++ b/src/samples/mini/posix/CMakeLists.txt
@@ -5,7 +5,7 @@
 
 cmake_minimum_required(VERSION 3.20.0)
 
-project (ocre_sample_mini)
+project (ocre_sample_mini LANGUAGES C)
 
 include(../input_file.cmake)
 
diff --git a/src/samples/static_checks/posix/CMakeLists.txt b/src/samples/static_checks/posix/CMakeLists.txt
index 715f60a3..74b02fe5 100644
--- a/src/samples/static_checks/posix/CMakeLists.txt
+++ b/src/samples/static_checks/posix/CMakeLists.txt
@@ -5,7 +5,7 @@
 
 cmake_minimum_required(VERSION 3.20.0)
 
-project (ocre_cmd)
+project (ocre_cmd LANGUAGES C)
 
 add_executable(ocre_cmd
     ocre.c
diff --git a/tests/coverage/CMakeLists.txt b/tests/coverage/CMakeLists.txt
index 8d5ad563..fa0f0761 100644
--- a/tests/coverage/CMakeLists.txt
+++ b/tests/coverage/CMakeLists.txt
@@ -11,7 +11,7 @@ set(CMAKE_C_FLAGS
     "-fprofile-instr-generate -fcoverage-mapping"
 )
 
-project(OcreTestSourceCoverage)
+project(OcreTestSourceCoverage LANGUAGES C)
 
 add_subdirectory(../system/posix OcreSystemTests)
 
diff --git a/tests/leaks/CMakeLists.txt b/tests/leaks/CMakeLists.txt
index 306cd0b1..0a74c5c7 100644
--- a/tests/leaks/CMakeLists.txt
+++ b/tests/leaks/CMakeLists.txt
@@ -11,7 +11,7 @@ string(APPEND CMAKE_C_FLAGS
     "-fsanitize=address"
 )
 
-project(OcreLeaksCheckPosix)
+project(OcreLeaksCheckPosix LANGUAGES C)
 
 add_subdirectory(../system/posix OcreSystemTests)
 
diff --git a/tests/system/posix/CMakeLists.txt b/tests/system/posix/CMakeLists.txt
index b2537b8c..5bca6a2b 100644
--- a/tests/system/posix/CMakeLists.txt
+++ b/tests/system/posix/CMakeLists.txt
@@ -21,7 +21,7 @@ if (SANITIZER)
 )
 endif()
 
-project(OcreSystemTestPosix)
+project(OcreSystemTestPosix LANGUAGES C)
 
 add_subdirectory(../../.. ocre)