shoutbragger
A person who thinks what they are saying is so important, cool, interesting, and unique that they tell their coworker about it in a very loud voice, which can be heard clearly throughout the office despite cubicle walls and significant distance. Typically the other side of the conversation cannot be heard. Usually what the shoutbragger is talking about really isn't a big deal.
What is that shoutbragger talking about over there? Everyone knows about "WidgetName." I wish he would quiet down.