For example, I had to do a project a couple years ago with a group of students involving a special event. We had to create a greeting card for Saint Patricks day. We struggled in the beginning because we didn't understand each others concepts. When we spoke in terms of design, our concept started to form. The downside to using this language is that some principles of design language are not fully defined and can be misleading to others working with you.
I personally would only use the design language when in the right environment. Working at a design company would be a good example of this. I would not however use this when giving a public speech. To some, using such language would just sound like gibberish, and leave them with more questions then answers. When pitching a project idea, to say a former employer, I would simplify these terms, rather then use the full extent of which I learned. A great way to look at this would be to compare culture languages. If someone spoke spanish and no other language, you would want to use only that language, otherwise they wouldn't understand.