Dear community,
I was sad about the limited possibilities regarding the options for a custom language for the Garmin Express software.
As you know, Garmin express uses the default language of the operating system. Sadly the "express.exe.config" file in the installed folder does not contain a command line or a selection for a language. More sad is, that the program itself does not provide the option to switch between languages.
Here is how I solved the problem.
This is your Garmin Express folder:
\Garmin_Express\Garmin\Express\
In this folder, all languages are abbreviated by two capital letters. Now let's assume "DE" is the language of my OS (operating system) and the installation is now in German by default.
I want to switch to English right now.
First step:
Go to your default language folder, in my case "DE" and rename the file: "Express.resources.dll" to a different name, to have a backup copy, e.g. "Express.resources_backup.dll".
Now copy the file "Express.resources.dll" out of the folder of the desired language, e.g. out of "Garmin_Express\Garmin\Express\UK" to the folder of the default language of your OS, which is "DE" in my case.
Second step:
Go to the "Garmin_Express\Garmin\Express\locales" folder and find the .pax file of your OS language, e.g. "de.pak" and rename it, e.g. "de_backup.pak".
Now make a copy of the .pak-file of the desired language, e.g. "en-US.pak" and rename it to "de.pak".
Third step:
Start Garmin Express and check the language. If it's not the desired language, yet, reboot your system and enjoy the desired language.
I hope this helps you a bit to have more fun with the software.
Greetings from Germany
Attila