This probably works on other versions of Windows 7 too. Handwriting recognition for other languages is already included in Windows 7 Ultimate and Windows 7 Enterprise.
1. Find the download link for the Windows 7 language pack of the desired language and download the exe file.
Look for KB972813 if using Windows 7 RTM and KB2483139 if using Windows 7 SP1. Use x86 for 32-bit and x64 for 64-bit. The download links should point to download.windowsupdate.com.
2. Change the permissions of the folder in which the downloaded exe file is located so that deletion is denied.
Right click the folder, go to Properties, then Security, then Advanced, then Change Permissions, then deny both Delete subfolders and files and Delete for the current user. This will prevent the created lp.cab file from being deleted.
3. Run the downloaded exe file.
This will create a file named lp.cab in the same directory.
4. Set the permissions of the folder back to what they were originally.
Remove the Deny entry in the permissions.
5. Open a command prompt with administrator rights.
Press the Windows Logo key, then type
cmd and press CTRL+SHIFT+ENTER.
6. In the command prompt run the following command:
dism /online /add-package /packagepath:<path_to_cab_file>
<path_to_cab_file> is the path of lp.cab. This command takes a while to complete.
Handwriting should now be enabled for that language on the input panel. You may need to add the language to the language bar if it is not there yet. lp.cab may be deleted after it has been installed, but it’s best to keep it around as it seems the handwriting feature disappears every time Windows gets updated.