Have you ever spent a meaningful amount of time listening to a doctor talk in "doctor-ese"? Ever walked out of an appointment wondering "what did the doctor say?"
Health literacy is defined in Health People 2010 as: "The degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions" (source).
Health literacy is a two-way street - it holds providers responsible for using plain language that can be understood, and it holds patients responsible for asking questions - for "speaking up" - when they don't understand.
We can all relate to this. Now let's see if we can find a corollary that will apply to our craft.
Have you ever read a proposal, a marketing piece, a meeting agenda, that just baffled you? That failed to get to the point? That used an unreasonable amount of jargon, or assumed a high level of previous understanding of the topic being discussed?
Have you ever sat through a meeting and walked out wondering "what did that person say?"
I have. It stinks. And it's always been partially my fault every time it happened - because when I have a low "domain literacy" related to whatever was being discussed, I need to speak up and seek clarity if the speaker isn't offering it up.
I've learned through painful experience that there is no shame in not understanding, in asking for clarification, in seeking to state problems as plainly as possible.
Even the most intractably difficult issue benefits from plain language, from small words, from simple sentences. All of which should be delivered calmly, and unselfconsciously.
A smart sales guy I know makes a point of saying "I'm not smart enough to hide things, so I lay out my position up-front with my prospects so they know what I'm all about."
There is a lot about transparency these days - one sure way to become more transparent is to try to be less clever. One step we can take in this direction is to use plain language.
Now don't get me wrong - I'm still a huge a fan of the well-turned phrase and the perfect word. But when dealing with people with a lower domain literacy, less is more. You will be perceived as a smarter, more in-tune person by "dumbing-down" until you have either reached their level of domain liteacy or they learn enough to raise their own.