A. All roots ending in =o=, =ö=, =u=, =y=.
B. All dissyllables ending in =a=, =ä=, and polysyllables ending in =ta=
(=tä=) after =h=, =l=, =n=, =r=, =s=, =t=; =heittä=, _to throw_; =tappa=,
_to kill_; =armahta=, _to pity_; =sivalta=, _to strike_; =ymmärtä=, _to
understand_.
(1) In these verbs =a= or =ä= is always changed to =e= before the
termination of the passive, =kaata=, =kaadetaan=.
(2) Before the =i= of the imperfect, polysyllables always reject =a= or
=ä=, =pelasta=, =pelasti=, etc.
Dissyllabic verbs vary in their treatment of =a=, _though_ =ä= _is always
rejected_. If the vowel of the first syllable is =o= or =u=; then =a= is
generally rejected. =Otta=, _take_, imperfect =otti=; =muista=, =muisti=.
But if the vowel of the first syllable is =a= or =e=, the =a= of the
last syllable generally becomes =o=; =laula=, =lauloi=, _sing_; =anta=,
=antoi=, _give_. But a great number of verbs ending in =ta=, and having
=a= in the first syllable, use _both_ forms; =ahtoi= _or_ =ahti=, _blow_;
=karttoi= _or_ =kartti=, _to avoid_; =saattoi= _or_ =saatti=, _to lead_.
If a verb ending in =lta=, =nta=, or =rta= (or the corresponding forms
in =ä=) elides the vowel before =i=, then =t= becomes =s=; =kieltä=, _to
deny_, =kielsi=; =kumarta=, _to adore_, =kumarsi=, etc. The same change
occurs after a long vowel in the forms =löysi=, _found_; =tiesi=, _knew_;
=taisi=, _knew how to_; =pyysi=, _asked_; =kaasi=, _threw down_; =huusi=,
_shouted_. Most verbs of this type, however, take =ti=, though some have
double forms.