Madoo,
I only know one way how you could change the translation of your Palm device.
First, you need to get
Jackflash from Brayder ($19.95). Ask them first if they support your device (Tungsten E) - I know the recent beta does support OS5 devices.
Second, you need to find someone who owns a Tungsten E in English. Ask him kindly to backup his ROM with Jackflash.
Then use Jackflash to restore his ROM to your device.
I've done that in the past with my old Palm Vx. Be aware that this method can thoroughly screw up your device if something goes wrong.
Maybe someone else knows a better way?