The similarities noted between many of the languages of Mesoamerica have led linguistic scholars to propose the constitution of a sprachbund, from as early as 1959. The proposal was not consolidated until 1986, however, when
Lyle Campbell,
Terrence Kaufman and
Thomas Smith-Stark employed a rigid linguistic analysis to demonstrate that the similarities between a number of languages were indeed considerable, with the conclusion that their origins were very likely caused by diffusion rather than inheritance, the standard criteria for defining a sprachbund. In their 1986 paper "Meso-America as a Linguistic Area" the above authors explored several proposed areal features of which they discarded most as being weakly attested, possibly by chance or inheritance or not confined to the Mesoamerican region. However, five traits in particular were shown to be widely attested among the languages, with boundaries coinciding with that of the Mesoamerican region and having a probable origin through diffusion. They then compared the five traits with the traits defining other language areas considered to be well-established, like the
Mainland Southeast Asia linguistic area and
Balkan language area. They concluded that by comparison the proposed Mesoamerican language area could indeed be considered a well-founded area: arguably "among the very strongest that are known". They also argued that some of the discarded traits might also be taken into consideration as strengthening the proposal, but they were not sufficient by themselves to act as foundation and other well-documented traits of a more
ethnolinguistic character might not be considerable as traits that are linguistic but cultural. == Traits defining the Mesoamerican language area==