If I stand up in front of a crowd of people and give a speech, that is a monologue; literally, there is one speaker. If I am having a conversation with you, then it's a dialogue. There is a very big difference between communication in these ways (no duh).
I thought that I had lost my succinctness recently. I noticed that in every conversation I had, I kept wanting to talk and talk, always wanting to explain my points further (and I am not one to dominate a conversation). Sometimes people would interject while I was on a roll, and I would first feel insulted, but then I would realize that I had been speaking plenty.
It turns out that I hadn't lost my succinctness; I simply was not in the right mindset. I am so used to writing monologues. The fact that I write these posts every night means that I am always ready to shoot out a monologue. But dialogue is different.
Dialogue is where I am succinct. When I have a back and forth with somebody, I can make a claim and let them question it. I can support an idea, have them challenge it, and dispel their concerns. Succinctness can make people more invested in a conversation.
Monologue does not allow you to be succinct in the same way. There is no second voice that presents challenges or alternate opinions. You have to be both sides of your argument. You have to elaborate your points so that people understand what you mean at your core.
Just remember to use the right method for the right circumstances.