One of our functional requirements at work require running a piece of software over a Japanese environment — which means we’ll have to set up a Japanese flavor of Windows for the job.
Question is, can we just patch our Windows Vista/7 with Japanese MUI language packs for this? Are there any significant functionality differences between the English and Japanese versions of Vista/7 that forces us to perform a clean install of a Japanese Windows OS instead of just patching an English one?
It is as simple as downloading additional MUIs, the easiest way is to install them as optional updates from Windows Update.
However, a limitation is that additional language packs are only available on Enterprise and Ultimate editions.
As for downsides, the only one I can think of is that you may have to learn Japanese!