Hi and welcome!
The official Sharp EZaurus site is luckily still online, and they host an update to the latest version of the system software:
http://support.ezaurus.com/sl-c3000/update/c3000update/c3000update.aspBy looking at the included update files this seems to actually be a full system install, the archive contains also an hdimage1.tgz image, I might be wrong but I believe the dictionaries are installed on the internal microdrive:
http://support.ezaurus.com/sl-c3000/update/c3000update/c3000updatecard.asp・initrd.bin (approx. 4,337KB)
・zImage.bin (approx. 1,264KB)
・mversion.bin (approx. 16KB)
・updater.sh (approx. 7KB)
・hdimage1.tgz (approx. 19,734KB)
Otherwise, I'll check if I have a mirror of the original installation CD. I also have a SL-C3000 which I have bought second-hand from Japan, there's a high possibility the japanese dictionaries are still on the microdrive.
Varti