Utilizing two independently-coded databases representing 3700+ languages, authors investigate whether cold ecologies or otherwise-desiccated ecologies are less amenable to complex tonality in language. Languages with complex tonality are primarily found to be located in tropical regions and generally absent in desiccated environments, regardless of latitude.

Population size is generally assumed to play a pivotal role in the evolution of languages and cultures, but the expected patterns and potential mechanisms of change are unsettled. Theoretical models are limited by this uncertainty because they require making prior assumptions about language evolution. Using a sample of 20 Polynesian languages, authors test the effect of population size on the gain, loss, and total change of basic vocabulary words.

This article examines the universal tendency for languages, regardless of their historical relationships, to develop similar words for mother and father on the basis of nursery forms. Findings suggest that Ma, Na, Pa, and Ta are significantly more common sound classes denoting the mother or father.

Using ethnography, historical linguistics, paleoanthropology, and speech biomechanics, the present study examines the relationship between labiodentals and the post-Neolithic period with the introduction of agriculture and softer diets. The results offer support for the linguist, Charles Hockett's, hypothesis that the shift in bite configuration in the post-Neolithic period, as well as the persistence of overbite and overjet, facilitates and makes the articulation of labiodentals more prevalent. Using cross-cultural comparison, findings also reveal that societies that produce their food are more likely to evolve and keep labiodentals than those that are not food-producing. Contact with other societies is also a mode by which societies gain labiodentals. Lastly, the expansion of agricultural and food processing technology over time has been imperative to labiodental articulations.

How do subsystems of language evolve over time? It is commonly assumed that grammatical changes of language are slower than vocabulary changes. Using a Dirichlet process mixture model to analyze rates of language evolution in 81 Austronesian languages, the authors find that to the contrary, the grammatical features of language tend to change at a faster rate than basic vocabulary. Furthermore, their results show that grammatical features have higher rates of homoplasy, more frequent contact-induced change, and less deliberate differentiation than basic vocabulary.

This article explores the possible relationship between the cultural evolution of language, music, and genetic variation beyond the level of language families. Due to their linguistic diversity, the authors use a sample of 14 Northeast Asian societies with matching information on their music, genetics, and linguistic patterns. The variables measuring language are lexicon, phonology, and grammar. Then, the authors compare each variable's relationship to music and genetic variation. The results only show a significant correlation between grammar and genetic variation.

This study sampled over 4,012 language varieties, comparing their version of 40 generally universal words, such as body parts, water, the sun, pronouns, and common behaviors or animals. These language variations were tested in their association to "specific humidity," the variable used to represent ambient humidity of a language location. Results suggest negative association between the dryness of climate and the utilization of vowels, consitent with the idea that dry air affects the behavior of the larynx.

This article examines the relationship between sonority and climate. Results suggest that languages spoken in warmer climates have higher levels of sonority than languages spoken in colder climates.

This article focuses on environmental and social explainations for variations in sonority. As expected, results suggest that climate, vegetation density, and sexuality are associated with sonority.

This article adds nuanced findings to the previous generalization that high sonority of the vowel explains its more frequent use in warmer climates. The authors find that “speakers in warm-climate languages make more use of the so-called “sonorant” consonants, that is, consonants with some of the qualities of vowels” (123).