That's simply using an object oriented interface to a module. But to answer your question, modules can be viewed as language extensions. They use existing language syntax combined with their own documented interface. For more complex modules, learning the module's interface can be a lot like learning a sub-language.

Many of us here speak English, but many of us would be lost if we were asked to discuss a medical proceedure in medical terms. The medical terms are a subset of English (often based on Latin roots, etc.), but they happen to be a subset for which people outside of the medical industry are not proficient.

A new module can be a little like a medical journal that uses an unfamiliar subset of our familiar English language. You'll have to familiarize yourself with its terms (its user interface) before you'll be able to make sense of it. Fortunately, we don't need a degree in medicine to understand most modules' documentation...with the exception of modules written by TheDamian. ;)

I would tend to say no. Mini languages generally have their own syntax and semantics, whereas Perl modules usually have to follow standard Perl syntax and semantics. Granted, there are some people (*cough* TheDamian *cough*) who do things in their modules that might fit a "mini language" description, but I think that's the exception.

also TheDamian showed Trey Harris the way in Commands::Guarded which is a neat mini-language encapsulating certain Perl usage patterns

Quite certainly. An API gives you a vocabulary to describe some algorithm just like the core langauge itself does. They work on different levels, but the distinction is ultimately artificial. Functional programming languages have long advertised this fact, f.ex.

Makeshifts last the longest.

An API gives you a vocabulary to describe some algorithm just like the core langauge itself does.

And the cool thing about Perl is that it is so flexible that a module cannot only add to your vocabulary, it can also change the grammar of the language.

To a certain extent. Perl5 is not close to the most malleable language in that respect. Most functional languages are much further along and have been for a long time, and Perl6 will be a world apart from Perl5. (I can't wait — I've said before that the thought of TheDamian tinkering with Perl6 gives me the shivers, both in a good and bad way. ;-))

Makeshifts last the longest.