The hypothesis was not elaborated until 1979 when Brown and Witkowski put forth a proposal with 62 cognate sets and supposed sound correspondences between the two families. They also published two articles proposing a "Mesoamerican Phylum" composed of Macro-Mayan and other language families of Mesoamerica. This proposal was examined closely by Lyle Campbell and Terrence Kaufman who rejected the proposal because of serious flaws in the methodology that had been applied.