Pankaj Mathur I'm attempting to do the same thing. I'm integrating language packs into 1809. They show up in DISM when I mount the WIM offline, but when I deploy the WIM, they dont show up as being installed. Also, despite the information presented here, if I try to add the language packs in 1809 from a user account without admin rights, I get prompted for admin credentials. I've tried to work around this by installing the language packs within windows during deployment, but that's not working either, because, while the languages show up under the admin account, any domain account added must download and install them. It's a bit of a mess. Is it too much to ask that if I integrate language packs into the wim (for both Windows and WinRe) that they actually be present when the system is deployed?
 
Also, as far as setting languages through the unattend file, my understanding of it is that if you set a language as default in the unattend file, that will effectively make that the default language and change the SKU, requiring you to deploy different ISO's for upgrade per region? Cant we simply have en-US as the default, and pre-install additional languages that actually show up in the OS when it's deployed?