I feel that everyone could learn and apply the idea of having clear, concise language without jargon.
I've hear this notion called "international English". English spoken in a way that non-native speakers find relatively easy to understand and follow.
The hard part of this is that non-native speakers will rarely ask for this. It's a gift that you have to give, and a gift you have to encourage others to give. And most of all, it needs to be done in a way so as not to be condescending, by simply being clear.
I speak multiple languages fluently and people are always surprised when I share that my vocabulary is seriously limited. I learned it is an advantage. I am forced to use simple words to explain.
On the opposite end: I had a coworker, I only ever got about 30% of what he said. I thought it's my Japanese skills. He used complicated sentences and words all over the place. But when I asked other Japanese coworkers, they told me they could not understand him either.
Wouldn't that international english be the same simple english (e.g., https://simple.wikipedia.org/wiki/Main_Page)?
It's always interesting to watch how a bunch of non-native speakers of English from different countries sitting in a room can talk to each easily, but when a Brit or an American joins, the conversation immediately collapses.