An interview of Alan Kay:
But at PARC our idea was, since you never step in the same river twice, the number-one thing you want to make the user interface be is a learning environment—something that’s explorable in various ways, something that is going to change over the lifetime of the user using this environment. New things are going to come on, and what does it mean for those new things to happen?
... Even if the user is an absolute expert, able to remember almost everything, I’m always interested in the difference between what you might call stark meaning and adjustable meaning.
I did quite a bit of study on that over the years to understand the influence of having something that you can read. It’s known that our basic language mechanism for both reading and hearing has a fast and a slow process. The fast process has basically a surface phrasal-size nature, and then there’s a slower one. This is why jokes require pauses; the joke is actually a jump from one context to another, and the slower guy, who is dealing with the real meanings, has to catch up to it.
There have been many, many studies of this. This argues that the surface form of a language, whatever it is, has to be adjustable in some form.