The simple vowels =o=, =ö=, =u=, =y= are invariable, but =a=, =ä=, =e=,
=i= are subject to certain changes in the last syllable of a root.
=A. Ä.=
When the vowels =A= and =Ä= at the end of a root are followed by the
=i= characteristic of the imperfect tense, or plural, they undergo the
following changes:—
=6.= (1) =Ä= is always rejected in disyllables—e.g. =heitän=, _I throw_,
=heitin=, _I threw_.
=7.= (2) =A= at the end of disyllabic roots is rejected before =i=, if
the vowel of the first syllable is =o=, =u=, =uu=, =ou=, =uo=, =oi=, or
=ui=: but is changed into =o= if that vowel is =a=, =e=, =i=, =aa=, =ii=,
=ai=, =au=, =ei=, =eu=, =ie=, or =iu=. Thus =ottavat=, _they take_, past
=ottivat= (for =ottaivat=); =nuora=, _a cord_, =nuorilla=, _with cords_;
=tupa=, _a hut_, =tuvissa=, _in huts_. But on the other hand, =kala=, _a
fish_, =kaloiksi=; =annan=, _I give_, =annoin=, _I gave_; =kannan=, _I
carry_, =kannoin=, _I carried_.[5]
Disyllabic verbs, where the final =a= is preceded by =t=, can change
it into =o=, but generally reject it, =ahtoi= or =ahti=: =kaartoi= or
=kaarti=.
=8.= Derivatives of verbs in =ma=, =ja=, =va=, always reject the =a=:
=sanova=, =sanovia=; =ottaja=, =ottajia=; =puhuva=, =puhuvia=.
=9.= (3) Polysyllabic verbs always reject =a= and =ä= in the imperfect.
=Odotan=, _I wait_, =odotin=, _I waited_, etc. The rejection also
takes place in polysyllabic substantives ending in =-mpa=, =-mpä=,
and derivatives in =va=, =vä=, =sa=, =sä=, and those where =h= or any
vowel but =i= precedes the final =a=, e.g. =vanhempa=, =vanhemmille=;
=sanova=, =sanovina=; =vieraha=, =vierahille=; =kapea=, =kapeita=. But
should the final =a= be preceded by two consonants, or the penultimate
syllable contain the vowel =i=, =a= and =ä= become respectively =o= and
=ö=; =asia=, _a thing_, =asioissa=; =karitsa=, _a lamb_, =karitsoita=;
=kynttilä=, _a candle_, =kynttilöitä=, _candles_. But the words =isäntä=,
=emäntä= always reject =i=, =isännille=, =emännille=.
=10.= (4) In cases which come under none of these heads, e.g. such a word
as =peruna=, _potatoe_, =a=, =ä= can be either dropped or changed to =o=,
=ö=, =perunia= or =perunoita=, partitive case plural.
=11.= (5) =a= and =ä= change to =e= before the comparative suffix
=-mpa= in disyllabic words, and before the suffix =ta=, =tta=, of the
passive. =Vanha=, _old_, comparative =vanhempi=; =istutan=, _I plant_,
=istutetaan=, passive.
=12.= (6) The nominative sing. of superlatives (stem =-impa=), and of
caritive adjectives (stem =-toma=), drops =a=: =kovimpa= becomes =kovin=
(by rules =24=, =46=); and =viattoma=, _innocent_, =viaton= (=46=).
=13.= (7) =a=, =ä= become =i= in the nominative sing. of comparatives,
stem =kovempa=, nominative =kovempi=.
=E.=
=14.= (1) =E= is always rejected before =i=. =Kive-illä= becomes
=kivillä=, _with stones_; =Mere-illä=, =Merillä=.
=15.= (2) Dissyllables ending in =e= always change that vowel to =i=
in the nominative singular. Stems, =mere=, _sea_, =tuule=, _wind_,
nominatives, =meri=, =tuuli=.
The only important exceptions to this rule are the words =itse=, _self_,
and =kolme=, _three_. =Nukke=, _a doll_, is also found, and =sine=,
_blue_, is used as well as =sini=.
The stem =miehe=, _man_, makes =mies= in the nominative sing.
=16.= (3) Polysyllabic stems ending in =e= reject it in the nominative
sing. Stem, =sisare=; nominative, =sisar=, _a sister_.
=17.= (4) The final =e= of a disyllabic stem disappears in nouns before
terminations commencing with =t=, and in verbs before terminations
beginning with =k= or =n=, provided that =e= is preceded by any simple
consonant but =k=, =p=, =v=, =m=, or by a double consonant of which
the last letter is =t= or =s= (except =ht=). Thus from the stem =une=
(_sleep_), =vuore= (_mountain_), =vete= (_water_) (nominative, =vesi=),
come the forms =unta=, =vuorta=, =vettä=, and from the verbal stems
=tule= (_come_), =mene= (_go_), such forms as =tulkaa=, =tullut= (for
=tulnut=), =menkää=. =Lapse=, _a child_, forms =lasta=, for =lapsta=;
=veitse=, _a knife_, =veistä= for =veitstä=.
But =e= remains in the verbs =potea=, _to fall ill_, =tuntea=, _to know_,
and in =itse=, _self_, =suksi=, _snowshoe_, =sääksi=, _a gnat_, =ripsi=,
_an eyelash_, =viiksi=, _a moustache_, which form their partitives in
=itseä=, =suksea=, etc.
=18.= But in disyllabic words =e= is not rejected if preceded by =k=,
=p=, =v=, or =m=. Thus the stems =joke=, _river_, =läpe=, _a hole_,
=kive=, _stone_, =Suome=, _Finland_, form their partitives =jokea=,
=läpeä=, =kiveä=, =Suomea=.
=19.= Likewise =e= remains in disyllables where it is preceded by =ht=,
or by any two consonants of which the last is not =t= or =s=: =tähte=,
_star_, and =lehte=, _leaf_, form =tähteä= and =lehteä=. =Onne=,
_fortune_, and =hanhe=, _goose_, =onnea= and =hanhea=.
But =yksi=, _one_, and =kaksi=, _two_ (roots =yhte= and =kahte=), form
=yhtä= and =kahta= for =yhttä=, =kahtta=. =Lumi=, _snow_, is also an
exception and forms =lunta=. Also the verbal stems =teke= and =näke=:
infinitive, =tehdä=, =nähdä=.
=20.= In polysyllabic words the =e= is always suppressed: root
=kysymykse=, _a question_, partitive case, =kysymystä= for =kysymykstä=.
=I.=
=21.= (1) When =i= at the end of substantives meets the =i= of the
plural, the first =i= changes into =e=, =risti=, _cross_, =risteissä=.
This rule is however not always observed, and forms like =ristissä=
are used for the plural. But in other cases, when two =i=’s meet, the
first falls out, pres. =etsivät=, imp. =etsivät=, not =etsiivät=. In old
Finnish, words like =etseivät= are found.
=22.= (2) When =i= (generally owing to the dropping of a consonant) is
found between two vowels it becomes =j=. =Kaloia= becomes =kaloja=.
=23.= All these four vowels, =a=, =ä=, =e=, and =i=, are rejected
before the =-i= of the terminations of the superlative: =vanha=, _old_,
=selkeä=, _bright_, =suure=, _great_, =auli=, _liberal_, make in the
superlative =vanhin=, =selkein=, =suurin=, =aulin=.