IV. a. The nu-class (fifth or su-class); the syllable नु nu is added to the root: thus, सुनु sunu from √सु su press out; आप्नु āpnu from √आप् āp obtain.
b. A very small number (only half-a-dozen) of roots ending already in न् n, and also one very common and quite irregularly inflected root not so ending (कृ kṛ make), add उ u alone to form the present-stem. This is the eighth or tan-class of the Hindu grammarians; it may be best ranked by us as a sub-class, the u-class: thus, तनु tanu from √तन् tan stretch.
V. The nā-class (ninth or krī-class); the syllable ना nā (or, in weak forms, नी nī) is added to the root: thus, क्रीणा krīṇā (or क्रीणी krīṇī) from √क्री krī buy; स्तभ्ना stabhnā (or स्तभ्नी stabhnī) from √स्तभ् stabh establish.
604. These classes have in common, as their most fundamental characteristic, a shift of accent: the tone being now upon the ending, and now upon the root or the class-sign. Along with this goes a variatior in the stem itself, which has a stronger or fuller form when the accent rests upon it, and a weaker or briefer form when the accent is on theforms are to be distinguished as the strong stem and the weak stem respectively (in part, both have been given above). The classes also form their optative active, their 2d sing. imperative, their 3d pl. middle, and their middle participle, in a different manner from the others.
605. In the classes of the Second or a-Conjugation, the present-stem ends in a, and the accent has a fixed place, remaining always upon the same syllable of the stem, and never shifted to the endings. Also, the optative, the 2d sing. impv., the 3d pl. middle, and the middle par-