This principle is all about the words you use. It is important to use common language that is easily understandable. If someone using your website, dashboard, etc has to google several of the terms used, that is a problem.
When thinking about the language you use, think about your audience. Who is it? How do they talk and write? How well do they understand the details of your industry, etc.? For example, within the medical world, it may be understood that “cephalalgia” is a medical term for headache, but if you tell the average person that you have a cephalalgia they may wonder if that’s a disease or some kind of growth. That’s probably not what you want. With many viewers, you want to use language that the person with the least understanding will be able to follow. If there is not a way to take a concept and break it down, have a definition handy and accessible, such as in an annotation.
Another thing to consider is native language and the country your audience may be from. If you will have people from various countries viewing your site, having a language control could be important. Also, words in one country can mean something different in another. For example, in the U.S. when we ask for chips at a restaurant, we mean chips, right? Like Doritos or tortilla chips. But in some places chips refer to what we in the U.S. call fries. You’ve heard of “fish n’ chips” haven’t you? So keep that in mind in the case that you have an international audience.
Poor usage: It’s almost too easy to find this principle horribly implemented in error or notification messages. In fact, it can be downright comical:
Good usage: Perhaps one of the most experienced and worst examples of poor common language is html error pages like a 404 page. You’ve experienced those, so instead let’s look at some good ones.
Clarify with annotations
Allow for casual use