A third mode of representing the relations of grammar is by the symbolic use of vowels and diphthongs. In Greek, for instance, the distinction between the reduplicated present [Greek: didômi] and the reduplicated perfect [Greek: dedôka] is indicated by a distinction of vowel, and in primitive Aryan grammar the vowel _â_ seems to have been set apart to denote the subjunctive mood just as _ya_ or _i_ was set apart to denote the potential. So, too, according to M. Hovelacque, the change of _a_ into _i_ or _u_ in the parent Indo-European symbolized a change of meaning from passive to active. This symbolic use of the vowels, which is the purest application of the principle of flexion, is far less extensively carried out in the Indo-European than in the Semitic languages. The Semitic family of speech is therefore a much more characteristic type of the inflexional languages than is the Indo-European.
The primitive Indo-European noun possessed at least eight cases--nominative, accusative, vocative, instrumental, dative, genitive, ablative and locative. M. Bergaigne has attempted to show that the first three of these, the "strong cases" as they are termed, are really abstracts formed by the suffixes _-as_ (_-s_), _-an, -m, -t, -i, -â_ and _-ya_ (_-i_), the plural being nothing more than an abstract singular, as may be readily seen by comparing words like the Gr. [Greek: epo-s], and [Greek: ope-s], which mean precisely the same. The remaining "weak" cases, formed by the suffixes _-sma, -sya, -syâ, -yâ, -i, -an, -t, -bhi, -su, -i, -a_ and _-â_, are really adjectives and adverbs. No distinction, for example, can be drawn between "a cup of gold" and "a golden cup," and the instrumental, the dative, the ablative and the locative are, when closely examined, merely adverbs attached to a verb. The terminations of the strong cases do not displace the accent of the stem to which they are suffixed; the suffixes of the weak cases, on the other hand, generally draw the accent upon themselves.
According to Hübschmann, the nominative, accusative and genitive cases are purely grammatical, distinguished from one another through the exigencies of the sentence only, whereas the locative, ablative and instrumental have a logical origin and determine the logical relation which the three other cases bear to each other and the verb. The nature of the dative is left undecided. The locative primarily denotes rest in a place, the ablative motion from a place, and the instrumental the means or concomitance of an action. The dative Hübschmann regards as "the case of the participant object." Like Hübschmann, Holzweissig divides the cases into two classes--the one grammatical and the other logical; and his analysis of their primitive meaning is the same as that of Hübschmann, except as regards the dative, the primary sense of which he thinks to have been motion towards a place. This is also the view of Delbrück, who makes it denote tendency towards an object. Delbrück, however, holds that the primary sense of the ablative was that of separation, the instrumental originally indicating concomitance, while there was a double locative, one used like the ablative absolute in Latin, the other being a locative of the object.
