Iotation

Iotation is a linguistic phenomenon very characteristic of the Slavic languages. It should not be confused with palatalization, which is an entirely different process, although in many cases they appear simultaneously.

Iotation is an appearance of palatal approximant /j/ before a vowel at the beginning of a word or between two vowels in the middle of a word, creating a diphthongoid (a partial diphthong). In the Greek alphabet this consonant is represented by iota (ι), hence the name. For example, the English apple is cognate to Russian яблоко (jabloko); they both come from an Indo-European root *āblu-. As a result of this phenomenon, no native Slavic root starts with an or an, but only with a and, although other vowels are possible. This process is still partially productive in some rural areas.

As it was invented for the writing of Slavic languages, the original Cyrillic script has relatively complex ways for representing iotation, devoting an entire class of letters to deal with the issue; there are letters which represent iotified vowels; these same letters also palatalize preceding consonants, which is why iotation and palatalization are often mixed up. There are also two special letters (Ь and Ъ) that prevent that palatalization, but the first one itself palatalizes the consonant again, thus allowing combinations of both palatalized and non-palatalized consonants with . Originally they were super-short vowels and themselves. The exact use depends on the language; see Cyrillic script as used in Slavic languages.

The adjective for a phone which undergoes iotation is iotated. The adjective for a letter formed as a ligature of the Early Cyrillic I (І) and another letter (which is used to represent iotation) is iotified. Note that the use of a iotified letter does not necessarily denote iotation. Even a iotified letter which follows a consonant letter is not iotated in most orthographies, although iotified letters imply iotated pronunciation after vowels, soft and hard signs, as well as in isolation.