[Footnote 111:  We may assume that in these languages and in those of type D all or most of the relational concepts are expressed in “mixed” form, that such a concept as that of subjectivity, for instance, cannot be expressed without simultaneously involving number or gender or that an active verb form must be possessed of a definite tense.  Hence group III will be understood to include, or rather absorb, group IV.  Theoretically, of course, certain relational concepts may be expressed pure, others mixed, but in practice it will not be found easy to make the distinction.]

[Footnote 112:  The line between types C and D cannot be very sharply drawn.  It is a matter largely of degree.  A language of markedly mixed-relational type, but of little power of derivation pure and simple, such as Bantu or French, may be conveniently put into type C, even though it is not devoid of a number of derivational affixes.  Roughly speaking, languages of type C may be considered as highly analytic ("purified”) forms of type D.]

This conceptual classification of languages, I must repeat, does not attempt to take account of the technical externals of language.  It answers, in effect, two fundamental questions concerning the translation of concepts into linguistic symbols.  Does the language, in the first place, keep its radical concepts pure or does it build up its concrete ideas by an aggregation of inseparable elements (types A and C versus types B and D)?  And, in the second place, does it keep the basic relational concepts, such as are absolutely unavoidable in the ordering of a proposition, free of an admixture of the concrete or not (types A and B versus types C and D)?  The second question, it seems to me, is the more fundamental of the two.  We can therefore simplify our classification and present it in the following form: 
                       _
 I. Pure-relational _/ A. Simple
    Languages \_ B. Complex
                       _
II.  Mixed-relational _/ C. Simple
    Languages \_ D. Complex

The classification is too sweeping and too broad for an easy, descriptive survey of the many varieties of human speech.  It needs to be amplified.  Each of the types A, B, C, D may be subdivided into an agglutinative, a fusional, and a symbolic sub-type, according to the prevailing method of modification of the radical element.  In type A we distinguish in addition an isolating sub-type, characterized by the absence of all affixes and modifications of the radical element.  In the isolating languages the syntactic relations are expressed by the position of the words in the sentence.  This is also true of many languages of type B, the terms “agglutinative,” “fusional,” and “symbolic” applying in their case merely to the treatment of the derivational, not the relational, concepts.  Such languages could be termed “agglutinative-isolating,” “fusional-isolating” and “symbolic-isolating.”