Of course I use MUI MSI.
I have Found the bug here : http://www.itninja.com/question/adobe-reader-xi-mui-installation-does-only-install-english
In fact, two solution. Add locale folder (with all language files) directly with Acrobat Customization (it's strange but it works).
Or edit MSI and add LANG_LIST= with all language.
Bye
