A simple substitution experiment

[oshfdk]

I might recognize that this looked somewhat language like at the line ends, if I was paying attention, but I wouldn't be able to identify the language. If the vms is a cypher, I'm not even sure how a programmer trying a new approach would know they've decoded it if the plain text dropped out of a decipherment attempt unless they were familiar with that language, especially if the plain text as has sometimes been argued is itself anomalous (e.g unique example of a language or orthographic system, unusual dialect, extremely idiosyncratic).

You can collect samples of plaintext languages and use statistical and dictionary based scoring to estimate how close the result is to some plaintext language, but for this to work you need to have the right ballpark estimation of the set of languages you are trying to identify. I'm running some decoding attempts and if the plaintext language is far from what I expect it to be (say, it turns out to be Vietnamese or Armenian), then you are absolutely right, even if I get the correct cipher scheme, I won't be able to decode anything. In practice I think one needs some balance between the number of languages to try and the number of false positives one is willing to tolerate.