License keys are only specific to the edition (Home/Professional/Ultimate). Language and architecture (32-bit vs. 64-bit) do not affect the validity of a license key. You can use your Windows 7 license key in any language variant from MSDNAA and legally install any language of Windows 7.
MSDNAA sometimes will provide language packs for download even if you are not provided with an install disk for every language option. If you want to change the language after the fact, log in to MSDNAA, and look in the software list for
Windows 7 Language Pack - DVD (Multilanguage). This will download an ISO containing all of the language packs. Windows 7 Professional, which is the version provided by MSDNAA, does not have built-in support for switching the installed language pack; only Enterprise and Ultimate have this feature. However, you can use third-party tool Vistalizator to change the installed language pack. I have used this tool before, and it works well.
You could alternatively just download an ISO of Windows 7 Professional EN. See Where do I download Windows 7 (legally from Microsoft)? for download links.