A Gift of Dharma for 3.21.10
by Danny Fisher
Today’s quote is from Buddhadasa Bhikkhu (1906-1993), the Thai ascetic monk, public intellectual, and founder of the hermitage Wat Suan Mokkh. This is it:
People language is used by the ordinary people who don’t understand Dhamma very well and by those worldly people who are so dense that they are blind to everything but material things. Then, there is the language which is spoken by those who understand reality (Dhamma), especially those who know and understand reality in the ultimate sense. This is another kind of language. Sometimes, when only a few words or even just a few syllables are uttered, the ordinary listener finds Dhamma language paradoxical, completely opposite to the language he speaks. We can call it “Dhamma language.” You always must take care to recognize which language is being spoken.
People who are blind to the true reality (Dhamma) can speak only people language, the conventional language of ordinary people. On the other hand, people who have genuinely realized the ultimate truth (Dhamma) can speak either language. They can handle people language quite well and are also comfortable using Dhamma language, especially when speaking among those who know reality, who have already realized the truth (Dhamma). Amongst those with profound understanding, Dhamma language is used almost exclusively, unfortunately, ordinary people can’t understand a word. Dhamma language is understood only by those who are in the know. What is more, in Dhamma language it isn’t even necessary to make a sound. For example, a finger is pointed or an eyebrow raised and the ultimate meaning of reality is understood. So, please take interest in these two kinds of language–people language and Dhamma language.

Here is a further outline of the idea.
http://www.dharmaweb.org/index.php/Two_Kinds_Of_Language:_Everyday_Language_and_Dhamma_language
I am not certain of the author but perhaps it is the same. If someone knows for sure could they correct that wiki with author name.