Caleb Everett

Climate, vocal folds, and tonal languages: Connecting the physiological and geographic dots

Significance The sound systems of human languages are not generally thought to be ecologically adaptive. We offer the most extensive evidence to date that such systems are in fact adaptive and can be influenced, at least in some respects, by climatic factors. Based on a survey of laryngology data demonstrating the deleterious effects of aridity on vocal cord movement, we predict that complex tone patterns should be relatively unlikely to evolve in arid climates. This prediction is supported by careful statistical sampling of climatic and phonological data pertaining to over half of the world’s languages. We conclude that human sound systems, like those of some other species, are influenced by environmental variables. We summarize a number of findings in laryngology demonstrating that perturbations of phonation, including increased jitter and shimmer, are associated with desiccated ambient air. We predict that, given the relative imprecision of vocal fold vibration in desiccated versus humid contexts, arid and cold ecologies should be less amenable, when contrasted to warm and humid ecologies, to the development of languages with phonemic tone, especially complex tone. This prediction is supported by data from two large independently coded databases representing 3,700+ languages. Languages with complex tonality have generally not developed in very cold or otherwise desiccated climates, in accordance with the physiologically based predictions. The predicted global geographic–linguistic association is shown to operate within continents, within major language families, and across language isolates. Our results offer evidence that human sound systems are influenced by environmental factors.

Evidence for direct geographic influences on linguistic sounds: the case of ejectives.

We present evidence that the geographic context in which a language is spoken may directly impact its phonological form. We examined the geographic coordinates and elevations of 567 language locations represented in a worldwide phonetic database. Languages with phonemic ejective consonants were found to occur closer to inhabitable regions of high elevation, when contrasted to languages without this class of sounds. In addition, the mean and median elevations of the locations of languages with ejectives were found to be comparatively high. The patterns uncovered surface on all major world landmasses, and are not the result of the influence of particular language families. They reflect a significant and positive worldwide correlation between elevation and the likelihood that a language employs ejective phonemes. In addition to documenting this correlation in detail, we offer two plausible motivations for its existence. We suggest that ejective sounds might be facilitated at higher elevations due to the associated decrease in ambient air pressure, which reduces the physiological effort required for the compression of air in the pharyngeal cavity–a unique articulatory component of ejective sounds. In addition, we hypothesize that ejective sounds may help to mitigate rates of water vapor loss through exhaled air. These explications demonstrate how a reduction of ambient air density could promote the usage of ejective phonemes in a given language. Our results reveal the direct influence of a geographic factor on the basic sound inventories of human languages.

A closer look at a supposedly anumeric language

Languages without cardinal numbers are exceedingly rare, with only a few clearly documented cases. One such case is putatively Jarawara, an Arawá language that has been claimed to lack native number terms. Recently collected evidence demonstrating the existence of such native terms is described here. The terms in question were corroborated independently by seven Jarawara speakers. Additional evidence for these native numbers is provided via the description of an associated tally mark system traditionally employed by the Jarawara. Combined with previous published claims on other Arawá languages, the data presented here suggest that number terms existed in Jarawara and other Arawá languages prior to contact with non-indigenes.

A Survey of Contemporary Research on Amazonian Languages

Amazonian languages have long confounded linguists. The languages represent a large number of linguistic families, including Tupi, Je, Carib and Arawak, and the languages exhibit a wide variety of typologically-remarkable structural characteristics. Since the inception of the European colonization of Amazonia over four hundred years ago, missionary linguists have attempted to document the languages of the region. It is only relatively recently, however, that a large number of linguists at academic institutions have undertaken in-depth field research in the region. The author examines the current state of Amazonian linguistics. The history of language research in the region is first outlined, though the majority of attention is devoted to surveying significant field research that has been undertaken in the last decade. Some recent studies on morphology, syntax, phonetics, and psycholinguistics are highlighted. The reader’s attention is drawn to trends, related to both the methodology and content of the research. Despite some possible areas for improvement, it is suggested that much of the recent work is of excellent quality, as evidenced by the fact that much of the research in question has drawn attention within linguistics and the cognitive sciences more generally.

Without Language, No Distinctly Human Numerosity

Coolidge and Overmann (2012) offer a fascinating perspective on the origin of human symbolic thought, suggesting that it may owe itself in part to the development of numerosity and concomitant neurological reconfigurations, particularly in the intraparietal sulcus. Yet their intriguing account, based in large measure on paleoanthropological data, is not informed by relevant experimental findings on numerical cognition (perhaps due to the recency of the findings). This is discomforting since reconcilability with experimental data is surely a sine qua non of any treatise on the genesis of symbolic thought. The findings in question suggest that Coolidge and Overmann’s account, while proffering valuable insights, nevertheless (a) underestimates the extent to which language shapes typical human numerosity and (b) errantly assumes a uniformity among extant homo sapiens vis-à-vis basic numerical cognition. Coolidge and Overmann rely on the strong possibility that “number concepts may be independent of language” (2012: 207), noting that populations such as the Pirahã speak an anumeric language. The Pirahã do lack precise number terms or morphosyntactic instantiations of number such as nominal plurality. Since theirs is the only experimentally verified case in which an autochthonous language lacks precise number terminology, it has played a central role in discussions of the language-numerosity nexus. Significantly, though, the most recent results obtained among the Pirahã (Everett and Madora 2012) demonstrate that the people struggle with merely differentiating quantities greater than three. Such results indicate that much of human numerosity is not dissociable from language, since most exact quantity recognition is dependent on numerical language and is not phylogenetically homologous. This pivotal aspect of human numerosity is largely absent in other species and among the Pirahã, excepting those Pirahã who have been familiarized with neologisms for precise numerosities (Everett and Madora 2012). Other recent research also demonstrates that much of the numerosity generally associated with our species relies predominantly on language. Spaepen et al. (2011) present experimental data gathered among anumeric adult Nicaraguan “homesigners,” an urban group of people with elaborate material technologies. Cru-

VARIABLE VELIC MOVEMENT IN KARITIÂNA

In Tupí-Karitiâna, there is a remarkable variety of nasal phones. Specifically, nasal consonants may take the form of simple nasals, pre-stopped nasals, post-stopped nasals, pre- and post-stopped nasals, as well as simple voiced stops. The greatest variety of nasal phones occurs when nasal consonants occur between two oral vowels. The analysis here focuses on the phones occurring in this environment. Acoustic data are presented, based on the spectral analysis of Karitiâna words with inter-oral nasals. The duration of velic movement in such words is shown to be wide-ranging and generally unpredictable, for all eight speakers examined. The remarkable extent of variability of velic movement observed contravenes expectations based on the literature on nasality.

Languages in drier climates use fewer vowels

This study offers evidence for an environmental effect on languages while relying on continuous linguistic and continuous ecological variables. Evidence is presented for a positive association between the typical ambient humidity of a language’s native locale and that language’s degree of reliance on vowels. The vowel-usage rates of over 4000 language varieties were obtained, and several methods were employed to test whether these usage rates are associated with ambient humidity. The results of these methods are generally consistent with the notion that reduced ambient humidity eventually yields a reduced reliance of languages on vowels, when compared to consonants. The analysis controls simultaneously for linguistic phylogeny and contact between languages. The results dovetail with previous work, based on binned data, suggesting that consonantal phonemes are more common in some ecologies. In addition to being based on continuous data and a larger data sample, however, these findings are tied to experimental research suggesting that dry air affects the behavior of the larynx by yielding increased phonatory effort. The results of this study are also consistent with previous work suggesting an interaction of aridity and tonality. The data presented here suggest that languages may evolve, like the communication systems of other species, in ways that are influenced subtly by ecological factors. It is stressed that more work is required, however, to explore this association and to establish a causal relationship between ambient air characteristics and the development of languages.

Independent cross-cultural data reveal linguistic effects on basic numerical cognition

Abstract The role of numeric language in basic numerical cognition is explored via the consideration of results obtained in two recent independent studies, one with Nicaraguan homesigners and one with speakers of Pirahã. Attention is drawn to remarkable parallels between the relevant findings, parallels that provide compelling evidence that adults without access to numeric language face difficulties when simply attempting to differentiate quantities greater than three.

From patterns in language to patterns in thought: Relativity realized across the Americas

Among the many results Boas envisioned for the documentation of American indigenous languages was a clearer delineation of some fundamental facets of human psychology. This paper examines the subsequent realization of that particular vision, outlining some of the ways in which research with speakers of American languages has helped illuminate human cognition. The focus is on key findings that offer support for linguistic relativity, the influence of linguistic disparities on thought evident in non-linguistic behavior. These findings relate to spatial, temporal, and numerical cognition. The relevant data surveyed offer compelling evidence that some cross-linguistic differences impact cognitive habits. A pivotal point is underscored throughout the paper: Despite the crossfield nature of the findings on this topic, those findings are ultimately contingent on the research of linguistic fieldworkers who have meticulously described typologically distinct languages. Through their research, the Boasian vision for psychological insights via the description of American languages has been realized.

Lexical and Grammatical Number Are Cognitively and Historically Dissociable: A Comment on Overmann 2015

It is by now well established that humans, like many other species, are natively equipped with two capacities associated with numerical cognition—an object file or exact number system (ENS) for discriminating quantities smaller than four and an approximate number system (ANS) for estimating larger quantities. Only in humans, however, are these capacities united, and the extent to which language plays a role in their unification has beenamatterof significant experimental inquiry (Everett 2014). Overmann (2015) seeks to shed further light on the interaction between numerosity and language, suggesting a structuring effect of the former on the latter. This exploration is welcome, and I suspect that most cognitive scientists would agree wholeheartedly with her concluding statement that language should be placed in a holistic context with other elements that contribute to human rationality. Similarly, and pivotally, linguists would not disagree with another of her key points, the fact that grammatical number (GN) is neither necessary nor sufficient for the development of lexical number (LN). That is because the general dissociability of these two linguistic features has, in fact, been well established for decades. Some languages of Australia, for instance, have long been known to have rich systems of GN while exhibiting reduced complexity with respect to LN. Conversely, there are languages that lack GN features such as nominal plurality while concomitantly utilizing robust systems of LN (e.g., Karitiâna, an Amazonian language that has been the subject of extensive research). Detailed views on the disparate motivations of LN and GN have been offered in the literature. For example, Dehaene (2011) suggests that innate number sense structures GN and small lexical numbers, while acknowledging that not all numeric language is structuredbynumerosity in such a straightforward fashion. Instead, human anatomy typically structures systems of LN in a largely independent manner, as evidenced by crosslinguistically recurrent quinary, decimal, and vigesimal bases. In turn, LN influences our numerical cognition in fundamental ways (Everett 2014). Overmann devotes considerable effort to arguing against the case that GN serves as somediachronic intralinguistic precursor to LN. But it is unclear who would maintain such a problematic position in