A few users asker how to select language for spell checking in the code comments. Egil Hansen (see comments to http://blogs.msdn.com/webdevtools/archive/2007/12/13/spell-checker-for-html-asp-net-jscript-vb-c-css-and-c-for-visual-studio-2005-and-2008.aspx#comments) discovered Microsoft Office 2007 Language Settings application in the Office Tools folder:

 You can use it to change default editing language in Office application and it should also change default language in the spell checker add-in.