My verbal communication skills improved attending college, obviously expanded my vocabulary, and then as I've worked in different positions the longer you're there and you actually understand the context, being able to explain yourself, processes, and know that people rely on understanding what you're saying. My listening skills have always been pretty decent and I've done that by being a an active listener and not actually waiting to respond, not thinking what I'm going to say, but actually focusing on what they're saying, asking enough questions to also understand what they're saying.