lately from Tai, Chinese, Tibetan, Malay, and other languages. During the Iron Age about 2,500 B.P., relatively young Austroasiatic branches in Indochina such as Vietic, Katuic, Pearic, and Khmer were formed, while the more internally diverse Bahnaric branch (dating to about 3,000 B.P.) underwent more extensive internal diversification. By the Iron Age, all of the Austroasiatic branches were more or less in their present-day locations, with most of the diversification within Austroasiatic taking place during the Iron Age. Paul Sidwell (2018) considers the Austroasiatic language family to have rapidly diversified around 4,000 years B.P. during the arrival of rice agriculture in Indochina, but notes that the origin of Proto-Austroasiatic itself is older than that date. The lexicon of Proto-Austroasiatic can be divided into an early and late stratum. 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 reconstructible in Proto-Austroasiatic) form part of the later stratum. Roger Blench (2017) suggests that vocabulary related to aquatic subsistence strategies (such as boats, waterways, river fauna, and fish capture techniques) can be reconstructed for Proto-Austroasiatic. Blench (2017) finds widespread Austroasiatic roots for 'river, valley', 'boat', 'fish', 'catfish sp.', 'eel', 'prawn', 'shrimp' (Central Austroasiatic), 'crab', 'tortoise', 'turtle', 'otter', 'crocodile', 'heron, fishing bird', and 'fish trap'. Archaeological evidence for the presence of agriculture in northern Indochina (northern Vietnam, Laos, and other nearby areas) dates back to only about 4,000 years ago (2,000 BC), with agriculture ultimately being introduced from further up to the north in the Yangtze valley where it has been dated to 6,000 B.P. 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. Austroasiatic dispersed coastal maritime routes and also upstream through river valleys. Khmuic, Palaungic, and Khasic resulted from a westward dispersal that ultimately came from the Red Valley valley. Based on their current distributions, about half of all Austroasiatic branches (including Nicobaric and Munda) can be traced to coastal maritime dispersals. 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. As early