The evolution of the consonantal palatal series in Common Slavic began after velars *k, *g, *x were changed before *ī̆, *ē̆. The softening solely of consonants which belong to the same local series, the changing of the point of their articulation and their affricatisation are diagnostic for the reconstruction of the First Palatation *k, *g, *x+​*ī̆, *ē̆>​*ḱ, *ǵ, *x́. The palatation exclusively of velars indicates the other consonants had no positional softening at that time.

The known Common Slavic alteration of velares in clusters «velar+yod», the origin of the palatal consonants *ĺ, *ń, *ć, *ʒ́<​*li̯, *ni̯, *ti̯, *di̯ and l-epenthesis after labial consonants (in clusters «labial+yod» show the so-called glide yotation, i. e. the interaction of consonants with i̯ (non-syllabic i) and not with j (the yod proper). After the yotation *ki̯, *gi̯, *xi̯>​*ḱ, *ǵ, *x́ and the First Palatation in Common Slavic the palatal series *ḱ, *ǵ, *x́ was formed; its members formed three correlated pairs: k — ḱ, g — ǵ, x — x́. The plosive palatals (non affricated) and fricative ones do not co-exist as usually in the same sub-system of phonemes and therefore the Common Slavic palatal series *ḱ, *ǵ, *x́ was not stable. By the time of yotations *si̯, *zi̯, *ti̯, *di̯>​*ś, *ź (>šʼ, *žʼ), *ć, *ǯ the affricatisation of *ḱ, *ǵ, *x́ was already ended.

After the yotations there existed at least four types of palatal series in Common Slavic dialects: *l, *ń, *ć, *ʒ́ and *l, *ń, *t́, *d́ in the South, *l, *ń, *čʼ, *ž, *šʼ in the East and *l, *ń, *ć, *ʒ́, *čʼ, *žʼ, *šʼ in the West; the latter variety was already an archaism in Common Slavic.

L-epenthesis in combinations «labial+yod» is one of the most important arguments of glide yotation generally and in Common Slavic in particular. Typological analysis indicates the phonetic de-epenthesation is possible only in the case when a palatal consonant used as epenthetical changes in all positions. Therefore the reconstruction of the phonetic transition *pĺ, *bĺ, *mĺ, *vĺ>​*pi̯, *bi̯, *mi̯, *vi̯>​pʼ, bʼ, mʼ, vʼ for the west Slavic languages and east Bulgarian dialects has no ground. The loss of l-epenthesis in these languages and dialects is due to the grammatical analogy.

The change both of point and mode of articulation of velars during the Second and Third «palatalisations» enable to reconstruct the palatation *k, *g, *x>​*ḱ, *ǵ, *x́ as a phonetic essence of these phenomena. The affricatisation *ḱ, *ǵ>​*ć, *ʒ́ and the assibilation *x́>​*ś were inevitable then due to the causes specified when studying the First Palatation. The new palatals had to interact with palatal series which existed in Common Slavic dialects. The result was the merging of all palatal phonemes in the West, the dispalatation *ć, *ʒ́, *ś>​c, ʒ, s in the South and the emergence of the new phonemes *ć, *ʒ́, *ś in the East.

The facts of yotations as well as the Second and Third Palatations in the presence of unchanged clusters C+​ī̆, ē̆ show the absence of positional palatalisation in Common Slavic up to the fall of jers. At the time of the latter change (or directly after it) in the west and east slavic languages the dispalatations *ĺ>​lʼ, *ń>​nʼ (except for Czech and Slovak dialects where ń was preserved), *ć>​cʼ, *ʒ́ (ź)>​zʼ took place, which could realize only in the presence of palatalised sounds and phonemes. Thus, the emergence of timbre correlation of palatalised — non-palatalised consonants caused the destruction of Common Slavic palatal series in the west and east Slavic languages. On the other hand, the preservation of this series in Serbocroatian, Slovenian and Macedonian show that there has never been positional softness (palatalisation) of consonants before front vowels in these languages.