One's ability to use simple words to describe complex concepts is a function of not just understanding of the concept itself, but also mastery of the language.

One's ability to use simple words to describe complex concepts is a function of not just understanding of the concept itself, but also mastery of the language. Consider that many (most?) of the research papers you've read were written by non-native English speakers. In my experience, people who are native English speakers have an easier time being both precise and concise.