What is technical debt? And how to talk about it?

Do you struggle prioritizing cleaning/refactoring/rearchitecting work against feature work? Do you have a hard time explaining why this might be more important than delivering business value? What is the relationship between technical debt and business value anyway? Understanding technical debt is difficult, talking about it is harder. Let's see if Mr Cunningham, DevOps, and the flow framework can give use some cues and tools to help us out.