A ubiquitous language is a shared vocabulary that everyone uses, and everyone understands. When someone says article, everyone knows what she is referring to. They know it’s not a press release or a blog post. If you don’t have a ubiquitous language, you’ll have people talking over one another. You could end up with content types like Press Release and News Item which both have similar fields and purposes. For some organizations, the difference might make enough sense to split them up, but if not, you have just overstructured your content with confusing redundancy.