diff --git a/railties/guides/source/api_documentation_guidelines.textile b/railties/guides/source/api_documentation_guidelines.textile
index 50e86e05a8..bab2be9188 100644
--- a/railties/guides/source/api_documentation_guidelines.textile
+++ b/railties/guides/source/api_documentation_guidelines.textile
@@ -35,7 +35,7 @@ Use the article "an" for "SQL", as in "an SQL statement". Also "an SQLite databa
 
 h3. English
 
-Please use American English (_color_, _center_, _modularize_, etc.). See "a list of American and British English spelling differences here":http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences.
+Please use American English (<em>color</em>, <em>center</em>, <em>modularize</em>, etc.). See "a list of American and British English spelling differences here":http://en.wikipedia.org/wiki/American_and_British_English_spelling_differences.
 
 h3. Example Code