1. A method of parsing ordered sequences of items comprising: accessing, at a processor, a process for generating ordered sequences of items, the process having one or more probability distributions representing possible ordered sequences of items involved in the process; receiving, at the processor, at least one example of at least part of an ordered sequence of items compatible with the probabilistic process; updating the one or more probability distributions by carrying out inference using the at least one example; and outputting information about the one or more probability distributions.