Roger Blench (2009) also proposes that there might have been other primary branches of Austroasiatic that are now extinct, based on substrate evidence in modern-day languages.
ɹˈɑːdʒɚ blˈɛntʃ tˈuː θˈaʊzənd nˈaɪn ˈɔːlsoʊ pɹəpˈoʊzᵻz ðæt ðɛɹ mˌaɪthɐv bˌɪn ˈʌðɚ pɹˈaɪmɚɹi bɹˈæntʃᵻz ʌv ˌɔːstɹoʊsɪˈæɾɪk ðæt ɑːɹ nˈaʊ ɛkstˈɪŋkt, bˈeɪst ˌɔn sˈʌbstɹeɪt ˈɛvɪdəns ɪn mˈɑːdɚndˈeɪ lˈæŋɡwɪdʒᵻz.