I still own the original version, not the GOG version of Startopia.

There used to be a patch that added the English language files to non-English versions of the game ("StarTopiaEnglish.exe"). Any fans here who know where I might find those? The old Eidos FTPs are unfortunately dead. :-(

Try this file:

http://www.gamefront.com/files/904906

Although, if you've patched the game to v1.01b, make a backup of the following files located at:
StarTopia\text\English\

FrontEnd.txt
Handbook.txt
index.txt
lev09.txt
option.txt
Patch1.txt

Then convert the game to the English language and copy those files back in the English text folder.

Thanks a lot :D