One of the big tenants of Domain Driven Design is “Ubiquitous Language”. This means that all the shareholders of the system a shared language. Product, Development, QA, Support, etc. all have a shared dictionary and language.
Existing Language
When Domain Driven Design is being kicked off on an existing project, this becomes a process of getting everybody to consolidate their language. All the terms already exists, but a dictionary needs to be agreed on. Each department, or even team, may call the same thing by different names. What Product calls “Requests” may be expressed in code as “Requisitions”. This disconnect causes confusion. At the very least it is extra context to hold in your head, to do the mental translation on the fly.
New Language
There is also a problem with new language. New terms are introduced, and need to be explained. Usually the first one to introduce the term gets the privilege of defining it. There are times when the first one to use the term is development. They then will need to go back to the rest of the business and teach them the term. And then add it to the dictionary.