The last three numbers in the AutoCAD version number (409) specify the language or locale. 409 is English.
If you are an ADN member, you can get the list of codes here:
http://adn.autodesk.com/adn/servlet/devnote?siteID=4814862&id=5413196&linkID=4900509
If not, you can get the value of this entry:
HKEY_CURRENT_USER\Software\Autodesk\AutoCAD\R18.0\CurVer
and it will tell you the correct version number and locale ID for the most recently used version.
Dave O.