Editing Iotation (section)

==Sound change==
Iotation occurs when a labial ({{IPA|/m/}}, {{IPA|/b/}}), dental ({{IPA|/n/}}, {{IPA|/s/}}, {{IPA|/l/}}) or velar ({{IPA|/k/}}, {{IPA|/ɡ/}}, {{IPA|/x/}}) consonant comes into contact with an ''iotated vowel'', i.e. one preceded by a palatal glide {{IPA|/j/}}. As a result, the consonant becomes partially or completely palatalized.{{sfn|Bethin|1998|p=36}} In many Slavic languages, iotated consonants are called "soft" and the process of iotation is called "softening".

Iotation can result in a partial [[palatalization (phonetics)|palatalization]] so the centre of the tongue is raised during, and sometimes after, the articulation of the consonant. There can also be a complete sound change to a [[palatal consonant|palatal]] or [[alveolo-palatal consonant]]. This table summarizes the typical outcomes in the modern Slavic languages:

{| class="wikitable" style="text-align: center;"
|- 
! colspan="3" | [[Labial consonant|Labial]]
! colspan="3" | [[Dental consonant|Dental]]/[[Alveolar consonant|alveolar]]
! colspan="3" | [[Velar consonant|Velar]]/[[Glottal consonant|Glottal]]
|- style="font-size: small;"
! origin
! partial
! complete
! origin
! partial
! complete
! origin
! partial
! complete
|-
| {{IPA link|p}} || {{IPA|pʲ}} || {{IPA|pj, pʎ}} 
| {{IPA link|t}} || {{IPA|tʲ}} || {{IPA link|c}}, {{IPA link|tɕ}}, {{IPA link|tʃ}} 
| {{IPA link|k}} || {{IPA|kʲ}} || {{IPA link|c}}, {{IPA link|tɕ}}, {{IPA link|tʃ}}
|-
| {{IPA link|b}} || {{IPA|bʲ}} || {{IPA|bj, bʎ}} 
| {{IPA link|d}} || {{IPA|dʲ}} || {{IPA link|ɟ}}, {{IPA link|dʑ}}, {{IPA link|dʒ}}
| {{IPA link|ɡ}} || {{IPA|ɡʲ}} || {{IPA link|ɟ}}, {{IPA link|dʑ}}, {{IPA link|dʒ}} 
|-
| {{IPA link|f}} || {{IPA|fʲ}} || {{IPA|fj, fʎ}}
| {{IPA link|s}} || {{IPA|sʲ}} || {{IPA link|ɕ}}, {{IPA link|ʃ}}
| {{IPA link|x}} || {{IPA|xʲ}} || {{IPA link|ç}}, {{IPA link|ɕ}}, {{IPA link|ʃ}}
|-
| {{IPA link|v}} || {{IPA|vʲ}} || {{IPA|vj, vʎ}}
| {{IPA link|z}} || {{IPA|zʲ}} || {{IPA link|ʑ}}, {{IPA link|ʒ}}
| {{IPA link|ɣ}} || {{IPA|ɣʲ}} || {{IPA link|ʝ}}, {{IPA link|ʑ}}, {{IPA link|ʒ}}
|-
| {{IPA link|m}} || {{IPA|mʲ}} || {{IPA|mj, mʎ, mɲ}} 
| {{IPA link|n}} || {{IPA|nʲ}} || {{IPA link|ɲ}}
| {{IPA link|h}} || {{IPA|hʲ}} || {{IPA link|ç}}, {{IPA link|ɕ}} 
|-
| || || || {{IPA link|l}} || {{IPA|lʲ}} || {{IPA link|ʎ}} 
|{{IPA link|ɦ}} || {{IPA|ɦʲ}} || {{IPA link|ʝ}}, {{IPA link|ʑ}}
|}
According to most scholars, the period of iotation started approximately in the 5th century, in the era of [[Proto-Slavic]], and it lasted for several centuries, probably into the late Common Slavic dialect differentiation. Here is an example from the early stage:{{sfn|Bethin|1998|p=36}}
* Proto-Slavic *''{{lang|sla|kĭasĭa}}''/kьасьа > Russian, Ukrainian, Macedonian, Bulgarian, Serbian '''{{lang|ru|чаша}}''' ''(čaša)'', Czech '''''{{lang|cs|číše}}''''', Croatian '''čaša'''