To account for contrasts found in Katuic languages, Paul Sidwell tentatively added *ʄ to the inventory reconstructed by Harry L. Shorto in 2006.
Shorto also reconstructed some forms using *ɯə and *ai, but Sidwell accounts for these using long vowels *aː, *ɛː and *iː.
[20] Roger Blench (2012) notes that Austroasiatic and Sino-Tibetan share many similarities regarding word structure, particularly nominal affixes (otherwise known as sesquisyllables or minor syllable prefixes).
Blench does not make any definitive conclusions about how these similarities could have arisen, but suggests that this typological diffusion might have come about as a result of intensive contact in an area between northern Vietnam, Laos, and northeast Myanmar.
Sidwell & Jenny & Alves (2020) further added, that the Munda noun incorporation system and referent indexation in predicates show internal head-first, verb-initial order, which can be taken as more archaic than the verb-final structures at clause/sentence level.
[22] Sora (Sora-Gorum, South Munda): paŋ-sum-t-amcarry-spirit-NPST-2SG.OBJpaŋ-sum-t-amcarry-spirit-NPST-2SG.OBJ'spirit will carry you away' (literally 'you will be spirit-carried')Bolyu (Pakanic): ɬjittsukill.dogɬjittsukill.dog'kill dog'Like the Tai languages, Proto-Mon–Khmer has an SVO, or verb-medial, order.
However, Paul Sidwell (2018) suggests that Proto-Austroasiatic may have in fact been verb-initial, with SVO order occurring in Indochina due to convergence in the Mainland Southeast Asia linguistic area.
He suggests the Sichuan Basin as likely homeland of proto-Austroasiatic before they migrated to other parts of central and southern China and then into Southeast Asia.
[40] Laurent Sagart (2011) and Peter Bellwood (2013) supported the theory of an origin of Austroasiatic along the Yangtze river in southern China.
[citation needed] Genetic and linguistic research in 2015 about ancient people in East Asia suggest an origin and homeland of Austroasiatic in today southern China or even further north.
[41] Integrating computational phylogenetic linguistics with recent archaeological findings, Paul Sidwell (2015)[11] further expanded his Mekong riverine hypothesis by proposing that Austroasiatic had ultimately expanded into Indochina from the Lingnan area of southern China, with the subsequent Mekong riverine dispersal taking place after the initial arrival of Neolithic farmers from southern China.
The early stratum consists of basic lexicon including body parts, animal names, natural features, and pronouns, while the names of cultural items (agriculture terms and words for cultural artifacts, which are reconstructable in Proto-Austroasiatic) form part of the later stratum.
Roger Blench (2018)[43][44] suggests that vocabulary related to aquatic subsistence strategies (such as boats, waterways, river fauna, and fish capture techniques) can be reconstructed for Proto-Austroasiatic.
[43] Hence, this points to a relatively late riverine dispersal of Austroasiatic as compared to Sino-Tibetan, whose speakers had a distinct non-riverine culture.
In addition to living an aquatic-based lifestyle, early Austroasiatic speakers would have also had access to livestock, crops, and newer types of watercraft.
Based on their current distributions, about half of all Austroasiatic branches (including Nicobaric and Munda) can be traced to coastal maritime dispersals.