Publications

Abstract

Language is supported by a distributed network of brain regions with a particular contribution from the left hemisphere. A multi-level understanding of this network requires studying the genetic architecture of its functional connectivity and hemispheric asymmetry. We used resting state functional imaging data from 29,681 participants from the UK Biobank to measure functional connectivity between 18 left-hemisphere regions implicated in multimodal sentence-level processing, as well as their homotopic regions in the right-hemisphere, and interhemispheric connections. Multivariate genome-wide association analysis of this total network, based on common genetic variants (with population frequencies above 1%), identified 14 loci associated with network functional connectivity. Three of these loci were also associated with hemispheric differences of intrahemispheric connectivity. Polygenic dispositions to lower language-related abilities, dyslexia and left-handedness were associated with generally reduced leftward asymmetry of functional connectivity, but with some trait- and connection-specific exceptions. Exome-wide association analysis based on rare, protein-altering variants (frequencies < 1%) suggested 7 additional genes. These findings shed new light on the genetic contributions to language network connectivity and its asymmetry based on both common and rare genetic variants, and reveal genetic links to language-related traits and hemispheric dominance for hand preference.

Abstract

The Ghana-Togo Mountain languages are a typologically distinct group of languages within the Kwa branch of the Niger-Congo language family. Until recently, they have received very little documentary attention, and are still greatly under-described. Where there is information regarding the tense, aspect, and mood system, Ghana-Togo Mountain languages are described as tense and aspect prominent. In contrast, Kwa languages are typically aspect and mood prominent, with little to no grammatical tense marking. Is the apparent greater emphasis on tense one of the typological features that separates the Ghana- Togo Mountain languages from the other Kwa languages? Or has tense been overrepresented due to the lack of description? In the case of Avatime, it is the latter. Previous accounts have described Avatime with a strong focus on tense. However, when the semantics are considered in more detail, we see that none of the forms contains an inherent specification for tense. While there is often a default interpretation in the past, present or future, this default can easily be overridden. Thus, Avatime has a typical Kwa system with a focus on aspect and mood and no grammatical tense.

Abstract

Name agreement (NA) refers to the degree to which speakers agree on a picture’s name. A robust finding is that speakers are faster to name pictures with high agreement (HA) than those with low agreement (LA). This NA effect is thought to occur because LA pictures strongly activate several names, so speakers need time to select one. HA pictures, in contrast, strongly activate a single name, so there is no need to select one name out of several alternatives. Recent models of lexical access suggest that the structure of the mental lexicon changes with experience. Thus, speakers should consider a range of names when naming LA pictures, but the extent to which they consider each of these names should change with experience. We tested these hypotheses in two picture-naming experiments. In Experiment 1, participants were faster to name LA than HA pictures when they named each picture once. Importantly, they were faster to produce modal names (provided by most participants) than alternative names for LA pictures, consistent with the view that speakers activate multiple names for LA pictures. In Experiment 2, participants were familiarised with the modal name before the experiment and named each picture three times. Although there was still an NA effect when participants named the pictures the first time, it was reduced in comparison to Experiment 1 and was further reduced with each picture repetition. Thus, familiarisation and repetition reduced the NA effect but did not eliminate it, suggesting speakers activate a range of plausible names.

Abstract

This study describes the sensory lexicon on the domains of colour, taste, shape, smell and touch of a rural sign language called Kata Kolok (KK). Taste was highly codable for Kata Kolok signers, who used a dedicated set of signs and facial expressions to indicate each of the taste stimuli. The second most codable perceptual domain was shape, for which signers often used classifiers and tracing gestures that reflected the shape of the object directly. Smell had a comparatively intermediate level of codability, but this was due, for the most part, to the use of evaluative terms. Although Kata Kolok has a dedicated set of colour signs, these leave large parts of the colour spectrum unnamed, resulting in low degrees of codability in this sensory domain. Unnamed colours were frequently described by iconic-indexical forms such as object labelling and pointing strategies. Touch was the least codable domain for Kata Kolok, which resulted in a wide range of iconically motivated constructions including a restricted set of domain-specific lexical signs, classifiers, tracing gestures, object labelling, and general evaluative terms.