Although Geiger's Grammar of the Sinhalese Language (1938) has cleared up admirably the main line in the historical development of this language, there still remains much to be done. Especially in the morphology of the verb there are many obscure points and in the following lines we shall try to unravel some of them.
1 The Sinhalese has three conjugations (paradigms:labanavā “to get”, badinavā “to fry”, tävenavā “to be heated”). Geiger explains the third conjugation from the MInd, passive: tävenavā < *tāvīya- < Skr. (causative passive) tāpyate (Geiger, § 140, 3), which coincides well with the fact that nearly all the verbs belonging to this conjugation are intransitive. As for the development ī > e compare elu: name of the old Sinhalese language < Sīhala, neranavā “to set aside, put out of the way ” < P. nīharati (Geiger, § 21, 3). So there can hardly be any doubt that this explanation is in the main correct. The -lya- is not always the passive-morpheme; thus Geiger mentions ālenavā “to adhere to” from Skr. āliyate; another case is pipenavā “to expand, open (of flowers)” from the denominative Skr. puspyati > *pupphīya- (other examples later in this article). Geiger derives vädenavā “to affect, concern, to be struck by an arrow” (Clough's dict.) from Skr. vrajati (Et. Gl.; Geiger gives the meaning “to strike against, to enter, intrude ”); I should, if the meaning given by Geiger is correct, prefer the derivation from āpadyate with loss of the initial vowel as in bisev “royal unction ” from abhiseka-, etc. (Grammar, § 30, 2); but it must be admitted that all the examples mentioned by Geiger contain short initial vowel.