I think that your only hope in the language department is to purchase an English version of the system software. I was checking the HP website and they are no longer selling the PPC/WM 2003 software but I would suggest that you check on ebay (I found this
link with a quick search of "ipaq 2003"). I am not sure what version you have (dont know what CE 3.0 converts to) - but 2003 is the newest that you can put on the device. I used to have a 3850 but that was a long time ago now!
If you want it in the english language then make sure that is what you are looking for - (if I remember correctly) each build is specific to the device and language option due to the size(s) of the system ROM.
BTW - I just grabbed the first ebay link that seemed to apply to your situation I did not check the seller or have any kind of relationship with them - it is just an example that these things exist out there for you.
Good luck - please post back to tell if this works for you!