Communicating in contextual ignorance

When A utters a declarative sentence in context to B, typically can mean proposition by the sentence, literally expresses (i.e. has truth-condition), there are propositions and B agree expressed, acquire knowledge from this testimonial exchange. In recent work on linguistic communication, each of these four platitudes been challenged, same basis: viz. ground that exactly which expressed is not discernible given information provided context. I argue that, even if true, will be propositional parts identified consequently, partial understanding afforded existence such identifiable undermines soundness arguments against platitudes.