diff --git a/reference/exec/functions/escapeshellarg.xml b/reference/exec/functions/escapeshellarg.xml
index 2ccefbdee687..6a4625f0b5a0 100644
--- a/reference/exec/functions/escapeshellarg.xml
+++ b/reference/exec/functions/escapeshellarg.xml
@@ -29,6 +29,11 @@
    Furthermore, each streak of consecutive backslashes (<literal>\</literal>)
    is escaped by one additional backslash.
   </para>
+  <para>
+   The behavior of this function with multibyte strings depends on the current
+   <constant>LC_CTYPE</constant> locale setting. Unrecognized characters will be
+   discarded. See <function>setlocale</function>
+  </para>
  </refsect1>
 
  <refsect1 role="parameters">
@@ -74,6 +79,7 @@ system('ls '.escapeshellarg($dir));
   &reftitle.seealso;
   <para>
    <simplelist>
+    <member><function>setlocale</function></member>
     <member><function>escapeshellcmd</function></member>
     <member><function>exec</function></member>
     <member><function>popen</function></member>
diff --git a/reference/exec/functions/escapeshellcmd.xml b/reference/exec/functions/escapeshellcmd.xml
index aa90a90f6e8a..f5e5a624d8b9 100644
--- a/reference/exec/functions/escapeshellcmd.xml
+++ b/reference/exec/functions/escapeshellcmd.xml
@@ -31,6 +31,11 @@
    plus <literal>%</literal> and <literal>!</literal> are preceded by a caret
    (<literal>^</literal>).
   </para>
+  <para>
+   The behavior of this function with multibyte strings depends on the current
+   <constant>LC_CTYPE</constant> locale setting. Unrecognized characters will be
+   discarded. See <function>setlocale</function>
+  </para>
  </refsect1>
 
  <refsect1 role="parameters">
@@ -107,6 +112,7 @@ $cmd = preg_replace('`(?<!^) `', '^ ', escapeshellcmd($cmd));
   &reftitle.seealso;
   <para>
    <simplelist>
+    <member><function>setlocale</function></member>
     <member><function>escapeshellarg</function></member>
     <member><function>exec</function></member>
     <member><function>popen</function></member>