Language Requirements and Considerations
A logical Team Foundation Server deployment, whether on one computer or two, can be configured to support one and only one language. If Team Foundation Server is deployed on two computers, both computers require the same configuration for both the Team Foundation Server language and operating system language.
An English Team Foundation Server may be installed on an English or Japanese operating system. A localized Team Foundation Server must be installed on the same language operating system or on an English operating system. For example, you can install a Japanese version of Team Foundation Server on an English or Japanese version of Windows Server 2003 but not on a German version of Windows Server 2003.
You must install the Windows SharePoint Services language pack that matches the Team Foundation Server language. For example, if you deploy the English version of Team Foundation Server on an operating system localized for another language, you must install the English language pack for Windows SharePoint Services. If you deploy a Japanese Team Foundation Server on an English operating system, you need to install the Japanese Windows SharePoint Services language pack.
You cannot install a version of Team Foundation Build in a different language from your version of Team Foundation Server.