We're working with an associational framework on English text. The psychology-based framework called
HAL (Hyperspace Analogue to Language) creates associations between words (or concepts depending on who you talk to) in text. You can then do some fun dimension reduction techniques like
LSA (Latent Semantic Analysis) or Concept Indexing or random projection. All of it is done in perl. We're not using PDL at the moment, but may do so in the future. If you're interested, our publications are
here - look at the top for the ECSCW paper for the most recent one.