Grambank reveals the importance of genealogical constraints on linguistic diversity and highlights the impact of language loss

While global patterns of human genetic diversity are increasingly well characterized, the diversity of human languages remains less systematically described. Here, we outline the Grambank database. With over 400,000 data points and 2400 languages, Grambank is the largest comparative grammatical database available. The comprehensiveness of Grambank allows us to quantify the relative effects of genealogical inheritance and geographic proximity on the structural diversity of the world's languages, evaluate constraints on linguistic diversity, and identify the world's most unusual languages. An analysis of the consequences of language loss reveals that the reduction in diversity will be strikingly uneven across the major linguistic regions of the world. Without sustained efforts to document and revitalize endangered languages, our linguistic window into human history, cognition, and culture will be seriously fragmented.

Learning speaker- and addressee-centered demonstratives in Ticuna

This study investigated the acquisition of demonstratives (e.g., this/that, here/there) by 45 children (1;0 - 4;11) learning Ticuna, an Indigenous Amazonian language with an unusually complex demonstrative system. I analyzed 89 10-minute samples from video recordings of child-caregiver interaction, examining how often children and caregivers produced each demonstrative type, as well as relationships among children's age, children's demonstrative production, and caregivers' production. Caregivers' demonstrative production displayed few relationships with children's age or production. Children produced speaker-proximal and speaker-distal demonstratives (this near me, that far from me) earlier in developmental time than addressee-proximal demonstratives (that near you), and nominal (this/that) demonstratives earlier than locative (here/there) ones. Compared to caregivers, children overused speaker-proximal demonstratives, but used other demonstrative types with adult-like frequency beginning at 2;0. These results support the view that cognitive biases toward egocentric, proximal, and semantically simpler items substantially influence children's acquisition of demonstratives.

A pressure cell for nonresonant inelastic x-ray scattering studies of gas phases

We report the design and performance of a gas-phase sample cell for measurements of momentum transfer (q) dependent nonresonant inelastic x-ray scattering (NRIXS). NRIXS measurements from He gas at 2 MPa (20 bars) readily demonstrate dipole-allowed and dipole-forbidden final states for two-electron excitations. Direct comparison of gas-phase NRIXS measurements with the corresponding nonresonant electron energy loss spectroscopy results (EELS) will be a valuable method for characterizing systematic errors in either technique for studies that require absolute normalization of the double differential cross section.