### Changes up to late proto-Finnic

1.  _\*ï_ > _\*a_. This change is shared by several other western Uralic languages, including the Sami and Mordvinic languages.
2.  _\*ä...ä_ > _\*a...e_.
3.  Word-initial deaffrication:
    *   _\*č_ > _\*š_.
    *   _\*ć_ > _\*ś_.
4.  _\*ŋ_ and _\*x_ are lost as phonemes. Between vowels they are usually lost entirely, triggering lengthening of a preceding vowel
    *   In certain cases, this may have proceeded through vocalization to _\*w_. Compare e.g. PU _\*mexi-_ > PF _\*möö-_ "to sell"; PU _\*sewi-_ > PF _\*söö-_ "to eat".
    *   Before dental/alveolar consonants, both consonants usually vocalize to _\*w_.
    *   The cluster _\*ŋk_ remains, but _\*ŋ_ in this case is now simply an allophone of _\*n_ rather than an independent phoneme.
5.  Depalatalisation:
    *   _\*ć_ > _\*c_.
    *   _\*ś_ > _\*s_.
    *   _\*δ́_ > _\*δ_.
    *   _\*ń_ > _\*n_.
    *   _\*ĺ_ > _\*l_.
6.  Lengthening of open vowels:
    *   _\*a_ > _\*oo_ (including former _\*ï_) and _\*ä_ > _\*ee_, when the vowels appear
        1.  in an open syllable, and
        2.  followed by a non-semivowel sonorant consonant (\*m, \*n, \*l, \*r, \*δ), and
        3.  followed by an original non-open vowel \*i (also denoted \*ə, \*e).
    *   E.g.: PU _\*ńäli-_ > PF _\*ńeele-_ "to swallow"; PU _\*ńëli_ > PF _\*nooli_ "arrow"
7.  _\*δ_ > _\*t_.
8.  Sequences of a vowel and syllable-final semivowel _\*j_ or _\*w_ are reinterpreted as diphthongs: _\*aj_ > _\*ai_, _\*aw_ > _\*au_ etc. Consequently, these consonants can no longer close a syllable (relevant for consonant gradation). Any diphthongs ending in _\*u_ become subject to vowel harmony and split into _\*u_ and _\*ü_ accordingly.
    *   In some cases, there remained alternations between the consonantal and vocalic form, e.g. in _\*käüdäk_ "to walk" ~ _\*kävi_ "walked" (Finnish _käydä_ ~ _kävi_).
9.  Monophthongisation of some diphthongs in non-initial syllables:
    *   _\*au_ > _\*o_
    *   _\*ei_ > _\*i_
    *   _\*eu_ > _\*u_, _\*eü_ > _\*ü_
10.  Word-final _\*-e_ becomes _\*-i_.
11.  _\*ti_ is assibilated to _\*ci_.
    *   The change was blocked if another coronal obstruent preceded, i.e. _\*tti_, _\*cti_, _\*sti_, _\*šti_ (thus Finnish _kaksi_ "two" ~ _kahden_ < Pre-Proto-Finnic _\*kakti_, but _lehti_ "leaf" ~ _lehden_ < _\*lešti_).
    *   The change was fed by _\*ei_ > _\*i_, which also caused assibilation.
12.  Apocope of final _\*-i_ when at least two syllables preceded. This occurred after assibilation, which created alternations between final _\*-c_ and medial _\*-t-_ in some nouns (e.g. Finnish nouns in _\-us_, genitive _\-uden_, essive _\-utena_).
13.  Syncope/contraction of medial _\*-e-_ between _\*c_, _\*l_, _\*n_, _\*r_, _\*s_, _\*š_, _\*t_ and a following _\*k_, _\*n_ or _\*t_. Syncope was prevented if more than one consonant followed the _\*-e-_. If more than one consonant preceded, consonant clusters were often simplified by dropping the first member of the cluster.
    *   Examples of syncope before _\*t_ are widespread, owing to the many endings beginning with this consonant, including the partitive singular, genitive plural, infinitive and various passive forms. Finnish examples are _vesi_ "water", partitive _vettä_ (< _\*vetetä_), _lohi_ "salmon", partitive _lohta_ (< _\*lošeta_), _purra_ "to bite" (< _\*purdak_ < _\*puretak_).
    *   Syncope before _\*n_ was also regular, but there were fewer environments in which it could occur. It occurred most notably in the potential mood and the past active participle of verbs. Many of the clusters ending in _\*n_ were later simplified by assimilation, either by assimilating the _\*n_ to the preceding consonant, or in some cases the reverse. Finnish examples are _purren_, _purrut_ (forms of _purra_ "bite"; < _\*purnen_, _\*purnut_ < _\*purenen_, _\*purenut_), _pessen_, _pessyt_ (forms of _pestä_ "to wash", < _\*pesnen_, _\*pesnüt_ < _\*pesenen_, _\*pesenüt_). Contraction also occurred in the essive singular of nominals, but these forms were often restored analogically. Finnish still possesses a few obsolete or fossilised cases of contracted essives, e.g. _toissa_ "on the second-last (time)" (< _\*toicna_ < _\*toicena_), a fossilised essive form of _toinen_ "second".
    *   Syncope before _\*k_ was regular but there were few environments in which it could occur. It is seen primarily in imperative forms of verbs, which are formed with a _\-k-_ suffix. Finnish examples are _olkaa_ (imperative of _olla_ "be"; < _\*olkade_ < _\*volekate_), _maatkaa_ (forms of _maata_ "lie down"; < _\*magatkate_ < _\*makatekate_).
    *   Syncope also occurred between _\*m_ and _\*t_ in several cases, giving _\*-nt-_. This occurred perhaps in all cases, but it was reverted later in many cases. An example in Finnish is _lumi_ "snow", partitive _lunta_ (< Pre-Proto-Finnic _\*lumeta_). Older Finnish had more examples of this, which were later restored by analogy.
    *   Two words show the contraction _\*-ket-_ > _\*-kt-_: _\*näktäk_ "to see" < _\*näketäk_ (Finnish _nähdä_) and _\*tektäk_ "to do" < _\*teketäk_ (Finnish _tehdä_).
14.  Application of radical gradation in closed syllables, causing voicing of short obstruents and shortening of geminate stops. This occurred after apocope, or was still productive at the time, as the newly consonant-final syllables resulting from apocope triggered gradation as well.
15.  _\*š_ > _\*h_
    *   The clusters _\*tš_ and _\*kš_ lose their first component to also become simple _\*h_.
16.  _\*č_ > _\*t_, but _\*čk_ develops differently in South Estonian, see below.
17.  In non-initial syllables, low-vowel i-diphthongs are raised:
    *   _\*äi_ > _\*ei_
    *   _\*ai_ > _\*oi_ when the preceding syllable contains a non-rounded vowel.
    *   _\*ai_ > _\*ei_ elsewhere.
    *   Some time after this change, _\*ei_ > _\*i_ again in non-initial syllables. This latter change occurred late in Proto-Finnic and did not trigger assibilation as the earlier _\*ei_ > _\*i_ change did. It also followed the southern Finnic backing of _\*e_ to _\*ë_ (Estonian _õ_ etc.) in back-harmony words, as only _\*ei_ was affected, while _\*ëi_ remained unchanged. Thus, different Finnic varieties show different outcomes, such as: _\*muna_ "egg", plural stem _\*munai-_ > _\*munei-_ > Finnish _muna_, _muni-_ but southern Finnic _munëi-_ > Votic _muna_, _munõi-_, Võro _muna_, _munnõ-_, Estonian _muna_, _mune-_ (with õ > e through loss of vowel harmony).
18.  Loss of glides before vowels:
    *   _\*ji_ > _\*i_. This change followed the preceding one, as former _\*eji_ becomes _\*ei_ but does not end up as _\*i_: _\*peni_ "dog", plural stem _\*peneji-_ > Finnish _peni_, _penei-_, Võro _pini_, _pin(n)e-_.
    *   _\*je_ > _\*e_ word-initially.
    *   _\*vu_ > _\*u_.
    *   _\*vü_ > _\*ü_.
    *   _\*vo_ > _\*o_. This change must have happened after Proto-Finnic broke up, as Estonian and Võro _võtma_ "to take" preserved the consonant until after the dialectal unrounding of _\*o_ to _\*õ_ (which prevented the change from affecting it). Compare Finnish _ottaa_, Veps _otta_, where it did apply as there was no unrounding in those dialects.

### Later developments

1. Development of consonant clusters
1. Developments to the affricates *c and *cc
1. The vowel õ
1. Vowel reduction and loss
1. Palatalization
1. Loss of final consonants
1. Loss of voiced obstruents
1. Lenition
1. Raising or diphthongization of long vowels
1. Diphthong assimilation
1. Coda vocalization
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