diff --git a/build/bin/sage-site b/build/bin/sage-site
index 400782164b3..5e00ec9a12f 100755
--- a/build/bin/sage-site
+++ b/build/bin/sage-site
@@ -153,8 +153,10 @@ if [ "$1" = "-docbuild" -o "$1" = "--docbuild" ]; then
     # proper UTF-8 operation in Python 3.6 or older.
     LC_ALL=$(locale -a | grep -E -i '^(c|en_us)[-.]utf-?8$' | head -n 1)
     LANG=$LC_ALL
+    LANGUAGE=$LC_ALL
     export LC_ALL
     export LANG
+    export LANGUAGE
 
     # See #30351: bugs in macOS implementations of openblas/libgopm can cause
     # docbuild to hang if multiple OpenMP threads are allowed.