diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 0d8c204..8d131bf 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -18,7 +18,7 @@ jobs:
     with:
       license_header_check_project_name: "Swift"
       api_breakage_check_enabled: false
-      unacceptable_language_check_enabled: false
+      unacceptable_language_check_enabled: true
       license_header_check_enabled: false
       broken_symlink_check_enabled: false
       format_check_enabled: false
diff --git a/Guest/Sources/dlmalloc/src/dlmalloc.c b/Guest/Sources/dlmalloc/src/dlmalloc.c
index a7ade59..1676a64 100644
--- a/Guest/Sources/dlmalloc/src/dlmalloc.c
+++ b/Guest/Sources/dlmalloc/src/dlmalloc.c
@@ -12,7 +12,7 @@
 // WebAssembly doesn't support shrinking linear memory.
 #define MORECORE_CANNOT_TRIM 1
 
-// Disable sanity checks to reduce code size.
+// Disable checks to reduce code size.
 #define ABORT __builtin_unreachable()
 
 // If threads are enabled, enable support for threads.
diff --git a/Guest/Sources/dlmalloc/src/upstream_malloc.h b/Guest/Sources/dlmalloc/src/upstream_malloc.h
index 51463f1..3311fee 100644
--- a/Guest/Sources/dlmalloc/src/upstream_malloc.h
+++ b/Guest/Sources/dlmalloc/src/upstream_malloc.h
@@ -3131,8 +3131,7 @@ static int init_mparams(void) {
     }
 #endif /* WIN32 */
 
-    /* Sanity-check configuration:
-       size_t must be unsigned and as wide as pointer type.
+    /* size_t must be unsigned and as wide as pointer type.
        ints must be at least 4 bytes.
        alignment must be at least 8.
        Alignment, min chunk size, and page size must all be powers of 2.