In Plain Common Language: Theology and Doctrine

"We must learn the language of our audience.  ... it is no use at all laying down a priori what the 'plain man' does or does not understand. You have to find out by experience."

... "you must translate every bit of your theology into the vernacular.  ... it is essential.  It is also of the greatest service to your own thought. ... if you cannot translate your thoughts into uneducated language, then your thoughts were confused. Power to translate is the test of having really understood one's own meaning." 

- - C. S. Lewis, essay "Christian Apologetics", in "God In the Dock"

"By trying to translate our doctrines into vulgar speech we discover how much we understand them ourselves.  Our failure to translate may sometimes be due to our ignorance of the vernacular; much more often it exposes the fact that we do not exactly know what we mean."

- - C. S. Lewis, essay "God In the Dock", in "God In the Dock"