When creating a macOS image using AutoDMG, the resulting image might not use the language you want.
To force an AutoDMG image to run the language chooser before anything else, you can add the file /private/var/db/.RunLanguageChooserToo to the image.
Create the file:
bash-3.2$ touch /private/var/db/.RunLanguageChooserToo
Use Packages or your preferred package creation tool to create a .pkg deploying the file to the correct location. Then add the .pkg file before you build the image using AutoDMG by adding it under Additional software.
AutoDMG images are useful for many things apart from deployment. For instance, they can be used with VMWare Fusion for testing purposes.
I’ll add a .pkg here soon, to save you the time making it.
Credits to the MacAdmins Slack community who helped me figure this out.