Without a specific example its hard to pin point why your conversations are like this, but what works for me is giving the other person a "conversational framew

Without a specific example its hard to pin point why your conversations are like this, but what works for me is giving the other person a "conversational framework" in which to fill out information, and giving reasons why that information will have influence on your mental model. But imprecise communication is something you'll have to get used to if you want to do important work. The most precise communication you will find are in higher level math textbooks, where the proofs rely on predetermined axioms and careful logic (and when proved these statements are called "trivial"). Issues in the real world are built on top of imperfect information. Reminds me of a Feynman quote on what makes a topic that we can have a discussion on: "We can talk about the weather; we can talk about social problems; we can talk about psychology; we can talk about international finance–gold transfers we can't talk about, because those are understood–so it's the subject that nobody knows anything about that we can all talk about!”