diff --git a/README.markdown b/README.markdown
index 5b2e7ba..ea6bf08 100644
--- a/README.markdown
+++ b/README.markdown
@@ -11,11 +11,13 @@ installing from this repository, add the following to your vimrc:
 
     autocmd BufNewFile,BufReadPost *.md set filetype=markdown
 
-If you want to enable fenced code block syntax highlighting in your markdown
-documents you can enable it in your `.vimrc` like so:
+To enable fenced code block syntax highlighting in your markdown
+documents add the following to your vimrc:
 
     let g:markdown_fenced_languages = ['html', 'python', 'bash=sh']
 
+**Note**: The fenced language names must be valid names of syntax files in vim's `syntax` folder. For example: `syntax/ruby.vim`.
+
 To disable markdown syntax concealing add the following to your vimrc:
 
     let g:markdown_syntax_conceal = 0