Aryon Rodrigues (2000) based this proposal on shared morphological patterns.

[4] The Je-Tupi-Carib proposal replaces earlier long-range hypotheses, e.g. Greenberg's phyla "Jê-Pano-Carib" (linking Macro-Je and Cariban to Panoan) and "Tupi-Arawak" (linking Tupian to Arawakan),[5] or Mason's "Macro-Tupí-Guaranían" family (1950: 236–238) which groups Tupian together with Bora–Witoto and Zaparoan.

[6] However, in some cases, similarities among the language families are clearly due to more recent linguistic diffusion, as with Tupian and Jê languages (Timbira; Guajajara, Tembe, Guaja, Urubu-Ka'apor, etc.)

[11] Non-cognate lookalikes or loans are identified by Nikulin (2023) as: Nikulin (2019) suggests a Macro-Chaco hypothesis linking Jê-Tupí-Cariban (including Karirian and Bororoan) with Mataco-Guaicuruan (possibly including Zamucoan):[10] In addition to likely shared morphology, there are also various possible Macro-Chaco shared basic vocabulary items, listed below.

[10] Reconstructed pronominal affixes of the protolanguages of the Macro-Chaco families are given in the following table:[citation needed] In this table the forms marked with (A) refer to ergative/agentive case, and the forms marked with (O) are referred to absolutive/patient/experiencer case.