A possible approach

My ultimate goal with Decl is, of course, not only to provide a quick way to bootstrap data-structure-heavy Perl scripts into being, but also to describe software systems at a high level and provide a framework to implement them.

So in that second sense, a semantic domain of "natural language processing" would describe tasks at a high level, describe the algorithms and approaches to take in performing those tasks, and would be amenable to at least some degree of automation in coding the tasks in other languages using various toolkits already available. In other words, the semantic domain encodes at least some of the professional knowledge about that domain that a seasoned programmer would be expected to have; a programmer-in-a-box solution.

To that end, and maybe in NLP to an extent that's a little unusual in comparison with other domains I've wanted to get into, there has to be a means of describing a given toolkit and its basic approach - a theoretical framework if you will - that allows a given task/algorithm to be expressed using it.

Not sure how that's going to happen yet; I just want to throw the gauntlet down here.

It looks like a lot of NLP toolkits are in Java, for whatever reason, with NLTK in Python being a strong contender. Nothing, really, in Perl. Which is why God moved Ingy to create Inline, of course, and Decl will be incorporating Inline very soon.