I'd like to make some of EE's built-in error messages more helpful to one site's users. And I know I can change these messages in EE system language files like
But since these files are part of the EE system (not 3rd party), what's the best way to maintain these changes so that they don't get overridden on EE updates, etc.?
For some context, these particular users are having some trouble understanding how to respond to error messages like
The email you chose is not available (an error that appears on registration). And, we're looking at a lot of things on the site other than EE system messages to prevent confusion / help site users.
But, as one small part of the overall strategy, we'd like to change some of these EE error messages.
Have you done this on any of your sites? How did you maintain these changes over time?
Or, if you have an alternative approach in EE (template-based? add-on-based?) that allows you bypass or override the EE system language files, I'd be interested in hearing about that too.