In general, however, the family is thought to have diversified too quickly for a deeply nested structure to have developed, since Proto-Austroasiatic speakers are believed by Sidwell to have radiated out from the central Mekong river valley relatively quickly.
ɪn dʒˈɛnɚɹəl, haʊˈɛvɚ, ðə fˈæmɪli ɪz θˈɔːt tə hæv daɪvˈɜːsᵻfˌaɪd tˈuː kwˈɪkli fɚɹə dˈiːpli nˈɛstᵻd stɹˈʌktʃɚ tə hæv dɪvˈɛləpt, sˈɪns pɹˈoʊɾoʊˌɔːstɹoʊsɪˈæɾɪk spˈiːkɚz ɑːɹ bᵻlˈiːvd baɪ sˈɪdwɛl tə hæv ɹˈeɪdɪˌeɪɾᵻd ˈaʊt fɹʌmðə sˈɛntɹəl mˈɛkɑːŋ ɹˈɪvɚ vˈæli ɹˈɛlətˌɪvli kwˈɪkli.