To start, the installation of language packs with Revit 2013 MUST occur during the initial installation of Revit. If you have already installed Revit and want to install a language pack, you'll need to uninstall and reinstall Revit to do so. If you end up uninstalling Revit 2013, I also recommend deleting the following folders and underlying files if they are not automatically removed by the uninstall:Revit install folder (The default location for this folder is C:\Program Files\Autodesk\Revit 2013.)C:\Users\All Users\Autodesk\RVT 2013\C:\Users\\AppData\Roaming\Autodesk\Revit\Autodesk Revit 2013
Next, you need to download the appropriate language pack. Please note that there are four "flavors"of Revit and there are unique language packs for each "flavor". The following are links to pages from which you can download language packs for each Revit "flavor":Autodesk Revit Architecture
Please note that if you are using the student version of Revit 2013 or the version that is included in the Building Design Suite, then you have Autodesk Revit (no industry designation) and will need the language packs specific to this flavor.
Once you've downloaded the language pack executable, you need to run it and extract the files to your local hard drive. At this point, you are ready to launch the Revit 2013 installation process. Navigate through the install as usual until you get to the Product Information page.
When browsing for the MSI fie, you must choose between the 32-bit and 64-bit version of the MSI file. Which version you need to select is driven by whether you are installing the 32 or 64-bit version of Revit. Here are examples of the path and file names for the 32-bit and 64-bit MSI files for the Revit 2013 Spanish language pack when extracted to the default location, C:\Autodesk:64-bit - C:\Autodesk\Autodesk_Revit_2013_Spanish_LP_Win_32-64bit\x64\es-ES\RVT2013\RVT2013LP.msi32-bit - C:\Autodesk\Autodesk_Revit_2013_Spanish_LP_Win_32-64bit\x86\es-ES\RVT2013\RVT2013LP.msi 2b1af7f3a8