Bubrich (
Бубрих ДВ · 1948 · Историческая фонетика финского-суоми языка: 71–79) discusses the idea suggested by L. Kettunen (1924 in "Virittäjä") that Baltic-Finnic experienced a shift
a/ä>e in non-initial syllables between two dentals (
r, l, n, t, s) belonging to the same syllable, e. g.:
Allative -lle<-llen<-len<*-la-n
Genitive Pl. -ten<*-ta-n (meidän etc. regarded as influenced by meijän)
Infinitives on -ten and -tessa (pestä : pesten, pestessä, antaa : antaen, antaessa), i. e. *-ta-k>-ta : *-ta-n>-ten, *-ta-sna>-tessa
Passive of the a-verbs, of which the vast majority possess stems ending on -ta-: nostettiin, nostettu; elettiin, eletty — thus, ajetaan must have been leveled after the predominant pattern
-ele- verbs: nostaa : nostella, later generalized to other cases, e. g. sanoa : sanella
kohta : kohden, vasta- (vastatuuli) : vasten, ylä (yläosa) : ylen.
Bubrich, however, mentions several cases when the shift
a/ä>e doesn't look conditioned by the position between the dentals.
One group consists of the
ne-verbs (
kova : kovenen, heikko : heikkenen; always trisyllabic), the Comparative (
kova : kovempi, also trisyllabic vs.
matala : matalampi), the
ea-verbs (where
e is generalized but it mostly follows
k: aueta, haljeta, poiketa, seldom
p: ruveta) and the
ea-adjectives (
aukea, selkeä) — however, the
ne-verbs,
ea-verbs and
ea-adjectives are interrelated (
selkeä- : selkene-), in particular the
ne-verbs use some
te-forms in their paradigm:
koveta<*kovet-ta-k, not
**kovenna<*koven-ta-k, kovettiin, not
**koventiin, kovetkaa not
**kovenkaa, while
kovennen and
kovennut can be interpreted as both
koven-ne-n, koven-nut and
<*kovet-ne-n, <*kovet-nut.
The other groups include nouns on
*-ek (
kastaa : kaste, estää : este, later extended to other cases),
-eh- (
pisara : pisare, rypälä : rypäle, murena : murene) and verbs on
-aksi-, -aksu- (hyväksyä) along with
-eksi-, -eksu- (
halpa : halveksia, kumma : kummeksia).
The case with
Suomi : suomalainen is even longer; it is discussed on pp. 45–57. Bubrich's explanation is that originally the final
a/ä was dropped in words with the uneven number of syllables, remained as
a/ä in bisyllabic words after a short open first syllable (and perhaps in some other cases) and turned into
i in all other cases, e. g.:
Nominative Singular, especially often after m: Suomi (suomalainen), luomi (luoma), lämmin, muudan, seitsen- (seitsenkertainen), ton-adjectives (dialectally -toin), istuin : istuma, synnyin (synnyinmaa) : syntymä, elin (elinpaikka) : elämä — these words were influenced by the types of nimi and sydän (Karelian sydäin) and switched to the e-stems
Superlative: -in originally belonged to the ma-stems as evidenced by Livvi Karelian; also Karelian has vasein, vasema- vs. the modified Finnish vasen, vasempa-.
Present Active participles: saapi : saavat, antavi : antavat
Essive: huomenna : eilen, ennen; kesken : keskenänsä, yksin : yksinänsä
Partitive: nyt<nyyt<*nykyt vs. tätä nykyä, perhaps minut, sinut, hänet, kenet, and secondarily meidät, teidät, heidät
Lative: taa<*taka-k (cp. taka-) vs. täällä<*tä-kä-lnä, tä-kä-läinen.