Editing Origin of language (section)

=== ''Ardipithecus ramidus'' ===
A study published in ''HOMO: Journal of Comparative Human Biology'' in 2017 claims that ''[[Ardipithecus ramidus]]'', a hominin dated at approximately 4.5 [[Mega-annum|Ma]], shows the first evidence of an anatomical shift in the hominin lineage suggestive of increased vocal capability.<ref name="Clark2017">{{Cite journal |last1=Clark |first1=Gary |last2=Henneberg |first2=Maciej |year=2017 |title=Ardipithecus ramidus and the evolution of language and singing: An early origin for hominin vocal capability |journal=HOMO |volume=68 |issue=2 |pages=101–121 |doi=10.1016/j.jchb.2017.03.001 |pmid=28363458}}</ref> This study compared the skull of ''A. ramidus'' with 29 chimpanzee skulls of different ages and found that in numerous features ''A. ramidus'' clustered with the infant and juvenile measures as opposed to the adult measures. Such affinity with the shape dimensions of infant and juvenile chimpanzee skull architecture, it was argued, may have resulted in greater vocal capability. This assertion was based on the notion that the chimpanzee vocal tract ratios that prevent speech are a result of growth factors associated with puberty—growth factors absent in ''A. ramidus'' ontogeny. ''A. ramidus'' was also found to have a degree of [[Neck|cervical]] [[lordosis]] more conducive to vocal modulation when compared with chimpanzees as well as cranial base architecture suggestive of increased vocal capability.

What was significant in this study, according to the authors,<ref name="Clark2017" /> was the observation that the changes in skull architecture that correlate with reduced aggression are the same changes necessary for the evolution of early hominin vocal ability. In integrating data on anatomical correlates of primate mating and social systems with studies of skull and vocal tract architecture that facilitate speech production, the authors argue that [[paleoanthropology|paleoanthropologists]] prior to their study have failed to understand the important relationship between early hominin social evolution and the evolution of our species' capacities for language.

While the skull of ''A. ramidus'', according to the authors, lacks the anatomical impediments to speech evident in chimpanzees, it is unclear what the vocal capabilities of this early hominin were. While they suggest ''A. ramidus''—based on similar vocal tract ratios—may have had vocal capabilities equivalent to a modern human infant or very young child, they concede this is a debatable and speculative hypothesis. However, they do claim that changes in skull architecture through processes of social selection were a necessary prerequisite for language evolution. As they write:

{{blockquote|We propose that as a result of paedomorphic morphogenesis of the cranial base and craniofacial morphology ''Ar. ramidus'' would have not been limited in terms of the mechanical components of speech production as chimpanzees and bonobos are. It is possible that ''Ar. ramidus'' had vocal capability approximating that of chimpanzees and bonobos, with its idiosyncratic skull morphology not resulting in any significant advances in speech capability. In this sense the anatomical features analysed in this essay would have been exapted in later more voluble species of hominin. However, given the selective advantages of pro-social vocal synchrony, we suggest the species would have developed significantly more complex vocal abilities than chimpanzees and bonobos.<ref name="Clark2017" />}}