Phonetic changes of Finno-Permic to Permic include (Sammallahti 1988):
· Complex vowel evolution, deriving:
o At a Pre-Permic stage:
§ PFP *u, *ü, * ū, *e → Pre-Permic *ɨ̆.
§ PFP *o(-a), *e̋ → Pre-Permic *ŭ.
§ PFP *i, *ī → Pre-Permic *ĭ.
§ PFP *a → Pre-Permic *u.
§ PFP *o(-i), *ō → Pre-Permic *u̇.
§ PFP *e(-i) → Pre-Permic *ü.
§ PFP *i(-a) → Pre-Permic *i.
§ PFP *e(-ä) → Pre-Permic *o.
§ PFP *i(-ä) → Pre-Permic *e.
§ PFP *ä → Pre-Permic *a.
o At a Proto-Permic stage:
§ A reduced *ü and low round *å are added to the paradigm
§ *a split into *ĭ, *ȯ, and *a, so that *ĭ occured in monosyllabic nouns, *a in (new or PFP) monosyllabic vocalic stems, *ȯ elsewhere.
§ Subsequently the non-back, non-front vowels split into back non-round and non-back round vowels: *ȯ → *e̋, *ȯ; *u̇ → *ɨ, *u̇.
· Minor changes in the consonant system, including:
· Retention of original qualities in internal positions, except a few irregular cases (cf. *bur ‘good’ < PFP *pe̋ra).
o Word internally:
§ Single intervocalic plosives disappeared; cf. PFP *śata ‘hundred’ → PP *śu.
§ Geminate stops became single; cf. PFP *keččä ‘sphere’ → PP *kič.
§ *č changed into *š which was voiced in voiced contexts.
§ *ś changed to *ć postnasally.
§ Single intervocalic obstruents became voiced; cf. PFP *pečä(-) ‘pine’ → PP *požim, PFP *kasi(u̯) ‘long’ → PP *kuź.
§ The dental spirant *d was lost or exchanged to *l which was nasalized adjacent to *m; *ð changed into *lj; cf. PFP *kuda- ‘weave’ → PP *kɨ̆-; PFP *vuði- ‘new’ → PP *vɨ̆lj;
§ Intervocalic *v and *x were lost or changed into *i̯; cf. PFP *kivi ‘stone’ →PP *kĭ.
§ Intervocalic *ŋ was lost or retained as a nasal; cf. PFP *i̯äŋi ‘ice’ → PP *i̯u̇.
§ Clusters consisting of a nasal and a plosive or an affricate were denasalised into single voiced stops or affricate; cf. PFP *lenti ‘pasture’ → PP *lud.
§ Nasals were lost before sibilants; cf. PFP *vanša ‘old’ > PP *våž.