The poverty of theological vocabulary results from the fact that most theologians are not full-fledged citizens of what Wordsworth called "the mighty world of eye and ear." They do not speak a "language of the sense." Theological vocabulary is the vocabulary of conception not perception.
Take from your shelf any commentary, introduction, history or systematic theology and look for words with some tactile, olfactory, visual, sonorous or saporous quality. They just aren't there. Theological vocabulary does not include honeysuckle, orange, shady, giggle, juicy, willow, brine, mud, clover, concrete, feathery, pudding, chimney and the like.
Someone may suggest that theological language is poor for not using "the language of the sense" only insofar as a steam engine is poor for not using gasoline. Indeed, perhaps the language of the sense is for poets, and the other kind of language is for theologians. Personally, I am not ready to concede that theology must be done in the desert while poetry roams through forests, mountains and meadows.
Waking Up to our Mighty World
But even if theological vocabulary must remain poor, the point I want to make is this: "The mighty world of the eye and ear" is always there for us. It is very sad when anyone passes through life oblivious to the joys this world can quicken—like that joyful motion in your chest when from atop Mount Wilson you can see the sun boil its way into the Pacific; or like the quiet gladness of rising before the sun and smog to join the happy birds in welcoming the day.
There is an intimate relationship, however, between our power to enjoy a sensuous experience and our capacity to describe it with words. In "Lines Composed Above Tintern Abbey" Wordsworth is not taken up nearly so much with the joy of revisiting the banks of the Wye as he is with the pleasure this moment will bring him in the coming years "recollected in tranquility."
To put it simply, without a full and rich language of the sense, we will lose the enduring quality of our sensuous joys, and, what's worse, with the atrophy of our descriptive capacities the power of all our enjoyment languishes. When you cease to use the word "tree" in your vocabulary, you have probably ceased to look at trees.
The Value of Stretching
The relation this has to theological vocabulary is this: The fastest and easiest way to obliterate the language of the sense and the power of the senses is to read only poverty-stricken theology. If we in seminary do not stretch ourselves beyond the pages of our dogmatics we shall all be dead by graduation day. And that evening, diploma in hand, we may lament with Samuel Coleridge,
All this long eve so balmy and serene
Have I been gazing on the Western Sky
And its peculiar tint of yellow green
And still I gaze—and with how blank an eye!