On Unicode installations of Caché, it is possible to use letters in variable names which are not ASCII letters.

For instance, a program written in Caché could have a variable named validación.

The problem, however, is that an attempt to compile this same program on a Caché installation with a different locale may cause this program to fail to compile. A Caché class with a variable name like the above will, for instance, fail to compile on a Japanese installation, as explained here.

For portability reasons, it is therefore preferable to only use ASCII letters in variable names.