 This shouldn’t come as a surprise, and it doesn’t result from a quirk or shortcoming of one particular human language, or of actual human languages as compared to other possible types of language. There is an in-principle problem with package-delivery communication of interestingly self-locating doxastic states. Precisely because they’re interestingly self-locating, such doxastic states aren’t the sort of thing that can uniformly be transmitted from speaker to addressee without leading addressees into error. This is easiest to see in an extreme case: It’s great for David Hume to be in the “I am David Hume” doxastic state. It’s not so great for anybody else to be in that state, and it’s not great for Hume to put his interlocutors in that state by communicating it package-delivery style.