(1) The root ends in a short vowel.
(2) The consonant at the beginning of the last syllable is liable to the
usual changes, when that syllable becomes closed.
(3) In the third person sing. present indicative the final vowel is
lengthened.
(4) The first infinitive has the termination =a= (=ä=).
(5) The root of the passive ends in =tta= (=ttä=), and hence the present
passive in =taan=.
(6) The first participle active _always_ ends in =va= (=vä=).