Sidwell (2022) proposes that the locus of Proto-Austroasiatic was in the Red River Delta area about 4,000-4,500 years before present, instead of the Middle Mekong as he had previously proposed.
sˈɪdwɛl tˈuː θˈaʊzənd twˈɛnti tˈuː pɹəpˈoʊzᵻz ðætðə lˈoʊkəs ʌv pɹˈoʊɾoʊˌɔːstɹoʊsɪˈæɾɪk wʌz ɪnðə ɹˈɛd ɹˈɪvɚ dˈɛltə ˈɛɹiə ɐbˌaʊt fˈoːɹ,zˈiəɹoʊzˈiəɹoʊ zˈiəɹoʊ dˈæʃ fˈoːɹ,fˈaɪvhˈʌndɹɪd jˈɪɹz bᵻfˌoːɹ pɹˈɛzənt, ɪnstˈɛd ʌvðə mˈɪdəl mˈɛkɑːŋ æz hiː hæd pɹˈiːviəsli pɹəpˈoʊzd.