2017-05-05: Updated to include Windows 10 1703 language pack details.
We’ve had a few Windows 10 releases now, and each release has its own set of language packs. For organizations with Windows 10 Enterprise E3 or E5 subscriptions (formerly called Software Assurance) we recommend that you get your media from the Volume Licensing Service Center (VLSC). Once there, you can access the downloads from the “Downloads and Keys” link.
Some have pointed out that it can be a little challenging to find the language packs corresponding to each release, so here’s a quick reference to point you to the right ones.
Windows 10 Enterprise 1511
This seems to be the one that people find most easily – even when it’s not what they’re looking for. To find this one, search for “Windows 10 Enterprise Language Pack” (or just “Windows 10 Enterprise” and find it in the list). When you click the “Download” link and then the “Continue” button, you’ll see one available ISO:
Notice the “Released Nov ‘15” text? That’s how you can tell it’s for Windows 10 1511. And notice that I selected “English” as the language, which then showed an ISO that contained every language pack. That becomes more important on the next one…
Windows 10 Enterprise 1607
The Windows 10 Enterprise 1607 language packs are published with a “MultiLanguage” language, which is why people usually struggle to find them. Change the “Language” drop down to “MultiLanguage” and then search to see this:
In this case “Released Jul ‘16” means Windows 10 1607.
Windows 10 Enterprise 1703
Just like with Windows 10 Enterprise 1607, you can find the language packs by selecting "Windows 10 Enterprise Language Packs" and then specifying "MultiLanguage" in the drop-down. Here's what you'll see:
So in this case "Release Mar'17" is Windows 10 1703.