Voiced postalveolar fricative

The voiced postalveolar or palato-alveolar fricative is a type of consonantal sound used in some spoken languages. The International Phonetic Association uses the term voiced postalveolar fricative only for the sound, but it also describes the voiced postalveolar non-sibilant fricative , for which there are significant perceptual differences, as one is a sibilant and one is not.

Voiced palato-alveolar fricative
The voiced palato-alveolar fricative or voiced domed postalveolar fricative is a type of consonantal sound, used in some spoken languages.

Transcription
The symbol in the International Phonetic Alphabet that represents this sound is the lower case form of the letter Ezh $⟨Ʒ ʒ⟩$, and the equivalent X-SAMPA symbol is. An alternative symbol used in some older and American linguistic literature is $⟨ž⟩$, a z with a caron. In some transcriptions of alphabets such as the Cyrillic, the sound is represented by the digraph $⟨zh⟩$.

Although present in English, the sound is not represented by a specific letter or digraph, but is formed by yod-coalescence of and  in words such as measure. It also appears in some loanwords, mainly from French (thus written with $⟨g⟩$ and $⟨j⟩$).

The sound occurs in many languages and, as in English and French, may have simultaneous lip rounding, although this is rarely indicated in transcription.

Features
Features of the voiced palato-alveolar fricative:

Occurrence
The sound in Russian denoted by $⟨ж⟩$ is commonly transcribed as a palato-alveolar fricative but is actually a laminal retroflex fricative.

Voiced postalveolar non-sibilant fricative
The voiced postalveolar non-sibilant fricative is a consonantal sound. As the International Phonetic Alphabet does not have separate symbols for the post-alveolar consonants (the same symbol is used for all coronal places of articulation that aren't palatalized), this sound is usually transcribed ⟨ɹ̠˔⟩ (retracted constricted ). The equivalent X-SAMPA symbol is.

Features
However, it does not have the grooved tongue and directed airflow, or the high frequencies, of a sibilant.
 * Its place of articulation is postalveolar, which means it is articulated with either the tip or the blade of the tongue behind the alveolar ridge.