Q:

The language is not supported on the server

I installed Language Packs for SharePoint Server 2010 from: 
https://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=3411 
On creating a new site collection using PowerShell with "Language" option set to 1034 or any other language code, I get the following error:
New-SPSite : The language is not supported on the server.
How do I fix this?

A:

I found this on support.microsoft, hope it helps. 
P.S: I did not test it.
1.) Open Registry Editor
2.) Expand HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Web Server Extensions\12.0
3.) Create a new Key under 12.0 called ServerLanguage
4.) Right-click ServerLanguage, select new String value and give it a name of 1033
Note: 1033 is valid for US English.  To determine the appropriate language value for other languages, see the following web site:  http://technet.microsoft.com/en-us/library/cc824907.aspx
5.) Close the Registry Editor
6.) Re-run the "SharePoint Products and Technologies Configuration Wizard"
The language is not supported on the server
The language is not supported on the server. 2

