Let me rephrase then. I think any programming language that allows users to define user-named symbols (variables and functions, if not macros, patterns, types, and objects) promotes creating dialects. In fact, I don't think it's possible to solve any interesting problem in a useful way without creating a new dialect!

I consider Spiffy to create a new dialect of Perl 5. I consider IO::All to create a new dialect of Perl 5. I consider CGI to create a new dialect of Perl 5.

Each of those modules adds capabilities that didn't previously exist. If you don't already know how to use them, you'll have to spend time learning them before you can really read and understand code that uses them. Using IO::All means certain things for using bitshift operators in some code. Using CGI in certain cases can do things to STDIN.

Just like most of the new language features in Perl 6, though, if you don't use them you won't pay for them.