Voiced alveolar fricatives are consonantal sounds. The symbol in the International Phonetic Alphabet that represents these sounds depends on whether a sibilant or non-sibilant fricative is being described.
A voiced alveolar sibilant is common across European languages, but is relatively uncommon cross-linguistically compared to its voiceless variant. Only about 28% of the world's languages contain a voiced dental or alveolar sibilant. Moreover, 85% of the languages with some form of are languages of Europe, Africa, or Western Asia.
A voiced alveolar non-sibilant fricative (also known as a slit fricative) is a consonantal sound in some spoken languages. As the International Phonetic Alphabet does not have separate symbols for non-sibilant alveolar fricatives, this sound can be transcribed by use of diacritics, such as (a retracted ) or (a raised , also often part of the affricate ). Additional symbols include (with the alveolar diacritic, in extIPA) and (a lowered ).
However, it does not have the grooved tongue and directed airflow, or the high frequencies, of a sibilant.
A few languages also have a voiced alveolar tapped fricative, which is simply a very brief alveolar non-sibilant fricative, with the tongue making the gesture for a tapped stop but not making full contact. It can be indicated in the IPA with the lowering diacritic to show that full occlusion does not occur, such as . Flapped fricatives are theoretically possible but are not attested.