Several features are related to the failure of prosodic forces and the forcing of vocables into new functions. One feature is the dispersion of vocables in a population. A critical point is reached when the majority of a population is able to accept a novel syntactic environment for a particular construction. In its use, this novel construction breaks the bounds of prosodic functions. The compensating measure that results from this dynamic often brings order changes, morphological transformations in syntactic expression and, more often than not, transcategorial changes.
Our research understands categories in syntactic constructions as emerging from extensive use of all vocables in a population of speakers and that all categories descend from lexical vocabulary. Therefore grammaticalization does not occur if language as a system is not widely shared in a population.
This assumption is corroborated in Sonia Ragir's observations about the emergence of grammatical sign languages, from proto-sign-languages in Martha's Vineyards, Guatemalan school for the deaf and the Caiman Islands [50]. Her findings show that, without the prompting of conversation in sign language between a critical number of individuals in a community, grammaticalization will not occur. Deaf children who are not given access to one another or who are not stimulated by family members to express themselves, live with rudimentary sign language skills that are very context-bound.
This account does not provide a clear description of competition in neural space in our ancestors, nor does it make any claim about the complexity of neural arrangements in our ancestors, however functionalization mechanisms remain in present forms of language and do facilitate its propagation. We may not be able to provide a model of what happened in hominid synaptic functions but an exploration of Calvin's model in the context of functionalized vocabulary may provide some historical clues.
The architectural constraints associated with synaptic functions interfere with prosody or prosody-related features such that the required causal flow in vocal transactions cannot be maintained. The failure may not be so much an inability as much as a taxation in perceptual cues that becomes too expensive in terms of neural space competition.