diff --git a/src/modules/README.md b/src/modules/README.md
index d7bcee54d..683ca9bc3 100644
--- a/src/modules/README.md
+++ b/src/modules/README.md
@@ -442,6 +442,9 @@ all be considered deprecated by the callback-enabled functions, above.
 - `check_target_env_call(command, stdin, timeout)` raises on a non-zero exit code.
 - `check_target_env_output(command, stdin, timeout)` returns a single string with the output of *command*, raises on a non-zero exit code.
 
+All of the API functions for running commands set the environment
+LC_ALL and LANG to "C" for the called command.
+
 
 ## PythonQt modules (deprecated)