Information depends on probability. If something is very probable then it doesn’t have much information (because you already saw it coming). If something is imp

Information depends on probability. If something is very probable then it doesn’t have much information (because you already saw it coming). If something is improbable then it has a lot of information. In the paper they want to know how much information is in a syllable in context. To do that they need to know the probability of each syllable given the previous syllable. To estimate that probability distribution, you need to look at a lot of text, much more than just the passages that the authors used to measure speech rate.