Index: manual/contribute/guides/writing_guide.rst
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--- manual/contribute/guides/writing_guide.rst	(revision 10027)
+++ manual/contribute/guides/writing_guide.rst	(working copy)
@@ -41,7 +41,7 @@
 Rules of thumb:
 
 - Spell checking is *strongly* recommended.
-- Use American English (e.g: modeling and not modeling, color and not colour)
+- Use American English (e.g: modeling and not modelling, color and not colour)
   also for formatting numbers (e.g: 2,718.28 and not 2 718,28).
 - Take care about grammar, appropriate wording and use simple English.
 - Keep sentences short and clear, resulting in text that is easy to read, objective and to the point.