diff --git a/source/performance.txt b/source/performance.txt
index 57e99e68ffb79bf695e1ca83d041d735809ac326_c291cmNlL3BlcmZvcm1hbmNlLnR4dA==..78c58258887b1426da186c839cfd559bbd015efc_c291cmNlL3BlcmZvcm1hbmNlLnR4dA== 100644
--- a/source/performance.txt
+++ b/source/performance.txt
@@ -63,10 +63,11 @@
   that uses something like ``ctypes`` for the interface.
 
 * **Missing RPython modules**: A few modules of the standard library
-  (like ``csv`` and ``cPickle``) are in C in CPython, but in pure Python
-  in PyPy.  Sometimes the JIT is able to do a good job on them, and
-  sometimes not. In most cases (like ``csv`` and ``cPickle``), we're slower
-  than cPython, with the notable exception of ``json`` and ``heapq``.
+  (like ``csv`` and ``cPickle``) are written in C in CPython, but written
+  natively in pure Python in PyPy.  Sometimes the JIT is able to do a
+  good job on them, and sometimes not.  In most cases (like ``csv`` and
+  ``cPickle``), we're slower than cPython, with the notable exception of
+  ``json`` and ``heapq``.
 
 We generally consider things that are slower on PyPy than CPython to be bugs
 of PyPy.  If you find some issue that is not documented here,