PHONOLOGY 109 lengthened. In other words any syllable may appear in the normal grade (a), the strengthened grade (d), or the zero grade. This gradation is of fundamental importance in Sanskrit grammar, and its importance was fully recognised by the Indian grammarians. They gave the name vrddhi to the strengthened grade and guna to the normal grade. The weak or zero grade they did not name because they cpnstructed their grammatical system in such a way that they started from the zero grade as the basic grade and from this they derived the guna and vrddhi grades by two successive processes of strengthening. The com- parative philologists differ from the Indian grammarians in that they regard the guna as the normal grade and from it derive the vrddhi and zero grades by the opposite processes of strengthen- ing and weakening. The operation of this gradation may be illustrated by a few examples : (1) Normal grade : sddas 4 seat sacate ‘ associates with padds, gen. sg. of pad - ' foot ghas- ' to eat J , dabhnoti 4 injures hdsati 4 laughs ^ (2) Extended grade : sdddyati 4 causes to sit rdtisicas nom. pi. ' associating with liberality pidam acc. sg. * foot ghdsd - ' fodder J , dddbhya- 4 that cannot be injured hdsa- 4 laughter (3) Zero grade : t sedur 4 they sat ' < *sazdur f cf . Av. hazdydt ' would sit sdicaii 3 plur. ' they associate upabdd- 4 trampling under foot a-dbh-uta- 4 wonderful' (literally ‘ that cannot be harmed, impregnable of divine beings), jaksiti 4 eats J (be. ja-ghs-i-ti) , jdksati 4 laughs ' (ja-hs-ati, cf. Vedic jdjjhati and Pa. jaggff&ti for different treatments of A + $). The same three grades apply to all suffixal elements. Thus in the case of the n-suffix we normal grade (guna) in voc. rijan f loc. r&jani zero grade in gen. sg. rdjnas, extended grade in acc. sg. rajdnam from the stem rijan - ' king The same grada- tion applies to all suffixal elements. Fundamentally this alternation a/djze to is all there is to the system of apophony. Some complications are caused by the combinations of a with semivowels, etc., and by some phonetic changes. These may be briefly summarised as follows : (i) When a is lost the semivowels (y t v) assume their vocalic form in the appropriate phonetic context : ydjati 4 sacrifices ' ; ijya 4 sacrifice ' ; vdpati 4 sows ' ; uptd - * sown When the semivocalic element comes second, i.e. in the diphthongs, the
