stylistic:tone
Typology

Regarding word structure, Austroasiatic languages are well known for having an iambic "sesquisyllabic" pattern, with basic nouns and verbs consisting of an initial, unstressed, reduced minor syllable followed by a stressed, full syllable. This reduction of presyllables has led to a variety of phonological shapes of the same original Proto-Austroasiatic prefixes, such as the causative prefix, ranging from CVC syllables to consonant clusters to single consonants among the modern languages. As for word formation, most Austroasiatic languages have a variety of derivational prefixes, many have infixes, but suffixes are almost completely non-existent in most branches except Munda, and a few specialized exceptions in other Austroasiatic branches.

The Austroasiatic languages are further characterized as having unusually large vowel inventories and employing some sort of register contrast, either between modal (normal) voice and breathy (lax) voice or between modal voice and creaky voice. Languages in the Pearic branch and some in the Vietic branch can have a three- or even four-way voicing contrast.

However, some Austroasiatic languages have lost the register contrast by evolving more diphthongs or in a few cases, such as Vietnamese, tonogenesis. Vietnamese has been so heavily influenced by Chinese that its original Austroasiatic phonological quality is obscured and now resembles that of South Chinese languages, whereas Khmer, which had more influence from Sanskrit, has retained a more typically Austroasiatic structure.