With the release of SharePoint 2010 SP1, it’s a good idea to include SP1 into your new builds. By slipstreaming the patches in your installation folder, this process gets much easier. This process is very similar to how things worked with WSS 3.0 and MOSS 2007. I’m going to use the file names for SP2010 Server in my examples. If you’re using SP2010 Foundation, please change the file names as needed. You will need to do the process for the language packs for every language that you wish to make available.
After doing this, copy the extracted files to the UPDATES folder of your Language Pack installation directory, making sure you match languages
Install each desired language pack. At the end of the process, everything in the updates folder will get processed.
Language packs installation cannot be slipstreamed into the install of SharePoint itself. Separate installers must be run.
This will not work for SP2 and Windows Server 2012!!!!! (It will for all other OS versions) http://blogs.office.com/b/sharepoint/archive/2013/07/23/check-out-the-sharepoint-server-2010-servic... Note: Due to required changes to the Prerequisite Installer, Service Pack 2 cannot be slipstreamed into installation media for use with installation on Windows Server 2012 systems. Installation of SharePoint Server 2010 with Service Pack 2 on Windows Server 2012 systems requires an integrated Service Pack 2 installation media due following the patch release.