This absolutely ancient (from 2015) blog post by Ben Clancy, then at the Department for Environment, Food & Rural Affairs (Defra), stands up rather nicely. Sometimes, it really is important to remind people why you use plain English. It can be helpful for your audience, sure. But also colleagues and teams that you work with from day to day.
This is super stuff from Nia Campbell at Content Design London. It's full of useful distinctions and information and a follow up to the International Organization for Standardization (ISO) launching its first plain language standard.
The bit about whether we should use the term 'plain' or 'clear' language caught my eye! I fussed for ages over whether I should call this newsletter Clear Language Weekly. In the end, I went for Plain English Weekly instead because I felt it was the more recognised phrase. People know it as a thing.
But as you may have spotted, I do generally prefer 'clear language' when I talk about the practical act of – you know – writing clearly.