A quick post on how to change the Windows display language with Powershell. You might use these commands based on any logic that determines the user's location/language. For instance, I created a script that gets executed on logon and sets the language based on some criteria (maybe an Active-Directory group or attribute).

Set-Culture en-US
Set-WinSystemLocale -SystemLocale en-US
Set-WinUILanguageOverride -Language en-US
Set-WinUserLanguageList en-US -Force
Set-WinHomeLocation -GeoId 244

You can find the right GeoID on Microsoft's website