Greg Ewing asked:

Would it help if an identifier were required to be made up of letters from the same alphabet, e.g. all Latin or all Greek or all Cyrillic, but not a mixture.

Probably, yes, though there could still be problems mixing within a program. FWIW, the Opera web browser is already using a similar solution. Domain names are limited to Latin-1 *unless* the top-level registrar has a policy to prevent spoofing. -jJ