Does anyone know the algorithm used by Turing's Colossus inference engine, so highly classified that the Brits kept it secret for decades after WW II?
Indeed, it may still be classified. Several years ago a colleague of mine, the late Robert Johnson, sent me an email response to my announcement about the Hutter Prize for Lossless Compression of Human Knowledge. Bob was the guy who designed the Burroughs zero address architecture used for so many years in banking (and incidentally invented magnetic ink used on checks). He certainly had a lot of background he didn't advertise, including classified work.
Computerdom does not have a lot of art in inference engines (making predictions). The most effective inference engine that I know of is the software done for Colossus, Turing's code breaking "computer" of WWII. The Brits still treat that software as classified even though the hardware has been declassified for years. So far as I know, nobody outside of UK knows the details of that software. My point here is that drawing understanding from natural languages is a relatively small art practiced mostly by cryptoanalysts. And my further point is that the natural language of interest (be it English, Chinese, Mayan or ...) has a major influence on how one (person or program) goes about doing analyses and making inferences. From a practical perspective, the Hutter challenge would be much more tractable for at least me if I could do it in Chinese. My first PhD student was Jun Gu who is currently Chief Information Scientist for PRC. His thesis was on efficient compression technologies. If you wish, you can share these thoughts with whomever you please.
Bob Johnson Prof. Emeritus Computer Science Univ. of Utah