Sign languages have two strikingly different kinds of morphological structure: sequential and simultaneous. The simultaneous morphology of two unrelated sign languages, American and Israeli Sign Language, is very similar and is largely inflectional, while what little sequential morphology we have found differs significantly and is derivational. We show that at least two pervasive types of inflectional morphology, verb agreement and classifier constructions, are iconically grounded in spatiotemporal cognition, while the sequential patterns can be traced to normal historical development. We attribute the paucity of sequential morphology in sign languages to their youth. This research both brings sign languages much closer to spoken languages in their morphological structure and shows how the medium of communication contributes to the structure of languages.

In this article we develop a semantic typology of gradable predicates, with special emphasis on deverbal adjectives. We argue for the linguistic relevance of this typology by demonstrating that the distribution and interpretation of degree modifiers is sensitive to its two major classificatory parameters: (1) whether a gradable predicate is associated with what we call an open or closed scale, and (2) whether the standard of comparison for the applicability of the predicate is absolute or relative to a context. We further show that the classification of an important subclass of adjectives within the typology is largely predictable. Specifically, the scale structure of a deverbal gradable adjective correlates either with the algebraic part structure of the event denoted by its source verb or with the part structure of the entities to which the adjective applies. These correlations underscore the fact that gradability is characteristic not only of adjectives but also of verbs and nouns, and that scalar properties are shared by categorially distinct but derivationally related expressions.

In this article we extend the model of language evolution exemplified in Ringe et al. 2002, which recovers phylogenetic trees optimized according to a criterion of weighted maximum compatibility, to include cases in which languages remain in contact and trade linguistic material as they evolve. We describe our analysis of an Indo-European (IE) dataset (originally assembled by Ringe and Taylor) based on this new model. Our study shows that this new model fits the IE family well and suggests that the early evolution of IE involved only limited contact between distinct lineages. Furthermore, the candidate histories we obtain appear to be consistent with archaeological findings, which suggests that this method may be of practical use. The case at hand provides no opportunity to explore the problem of conflict between network optimization criteria; that problem must be left to future research.

Researchers have long debated the means by which children learn the argument structure of verbs. Making syntactic generalizations often entails learning the semantics of different verbs, complicating and delaying the acquisition process. This study investigates four- to twelve-year-olds’ and adults’ knowledge of animacy hierarchy restrictions on postverbal word order in Sesotho double object applicatives, constructions where verb semantics is kept constant. Performance on forced-choice elicited production tasks showed that four-year-olds have early knowledge of the animacy hierarchy restrictions, providing evidence of syntactic generalization even on low-frequency constructions. Although there were no verb frequency effects, performance was also better on the highest-frequency animacy constructions. The results suggest that learning restrictions on verb-argument structure is facilitated when verb semantics is not a confound, but that construction frequency also plays a role in mastering the argument structure of verbs.