Edward Sapir (18841939). Language: An Introduction to the Study of Speech. 1921.
Concrete Relational Concepts (still more abstract, yet not entirely devoid of a measure of concreteness): normally expressed by affixing non-radical elements to radical elements, but generally at a greater remove from these than is the case with elements of type II, or by inner modification of radical elements; differ fundamentally from type II in indicating or implying relations that transcend the particular word to which they are immediately attached, thus leading over to
Pure Relational Concepts (purely abstract): normally expressed by affixing non-radical elements to radical elements (in which case these concepts are frequently intertwined with those of type III) or by their inner modification, by independent words, or by position; serve to relate the concrete elements of the proposition to each other, thus giving it definite syntactic form.
The nature of these four classes of concepts as regards their concreteness or their power to express syntactic relations may be thus symbolized:
I. Basic Concepts II. Derivational Concepts
III. Concrete Relational Concepts IV. Pure Relational Concepts
These schemes must not be worshipped as fetiches. In the actual work of analysis difficult problems frequently arise and we may well be in doubt as to how to group a given set of concepts. This is particularly apt to be the case in exotic languages, where we may be quite sure of the analysis of the words in a sentence and yet not succeed in acquiring that inner feel of its structure that enables us to tell infallibly what is material content and what is relation. Concepts