Finding the force: a novel word learning experiment with modals

This study investigates the semantic and pragmatic challenges of acquiring the force of English modals, which express possibility (e.g., might) and necessity (e.g., must). Children seem to struggle with modal force through at least age 4, over-accepting both possibility modals where adults would prefer necessity modals, and necessity modals in possibility situations. These difficulties are typically blamed on pragmatic or conceptual immaturity. In this study, we sidestep these immaturity issues by investigating the challenges of modal learning through a novel word learning experiment with adults, for different 'flavors' of modals: epistemic (knowledge-based) versus teleological (goal-based), and comparing novel modals with actual English modals. We find that when learning possibility modals, adult learners behave as expected: they accept novel modals in necessity situations, both in epistemic and teleological contexts, but less often after they've learned a pragmatically more appropriate necessity modal. However, when learning necessity modals, participants manage to learn the right force (i.e., reject them in possibility situations) for epistemic scenarios only; with teleological scenarios, they accept them in possibility situations. We propose that an overlap in modal flavor explains their behavior, specifically, the competition with an ability interpretation in teleological but not epistemic scenarios, which could also contribute to children's difficulty with necessity modals reported in the acquisition literature

Modal Development: Input-Divergent L1 Acquisition in the Direction of Diachronic Reanalysis (2015)

This thesis explores the proposed causal link between child language development and language change from the language acquisition perspective. While theorists have argued for a causal link between acquisition and change for over a century (Meillet, 1912; Paul, 1920; i.a.), but little research has investigated whether this proposal makes sense for child language (c.f. Baron, 1977; van Gelderen, 2011: 21-26; Cournane, 2014). I investigate whether child input- divergent patterns (i.e., analyses which diverge away rather than converge towards the adult target) are compatible with innovations we see in the historical record. I present a series of naturalistic and experimental studies focusing on modal expressions (e.g., must, can, have to, be going to) in English development. Modal expressions develop diachronically in a unidirectional manner: (a) syntactically, from verbs to functional verbs to INFL-elements (Roberts, 1985; i.a.), and (b) semantically, from root meanings (e.g., ability, obligation), to epistemic meanings (e.g., inference) (Traugott, 1989; i.a.). The studies in this thesis first propose what would need to be true of child language in order for child input-divergence to be the source of historical innovations, and second, test whether these input- divergent patterns indeed occur in child development.The corpus studies on naturalistic modal development provide evidence for syntactic re- categorization biases (i.e., for treatment of expressions which belong to lower categories like v in the input, as higher categories, like INFL, in the child grammar). These studies also show that the delayed onset of epistemic modal uses relative to root modal uses is best explained by grammatical development, not conceptual development (Papafragou, 1998; i.a.). The experimental studies provide evidence that preschool age children increasingly attribute epistemic-type interpretations to polysemous modal constructions, regardless of the presence or absence of meaning-determining aspect cues which adult speakers rely on (Condoravdi, 2002; Hacquard, 2006). Children appear to show U-shaped development for modal meaning and the direction of non adult-like meaning attributions is compatible with the diachronic root > epistemic trajectory. Taken together, the studies in this thesis show that children have persistent input- divergent developmental biases in both the syntactic and semantic development of their modal expressions. Both developmental patterns are consistent with the view that there are grammar internal biases in development towards treating modal expressions as increasingly abstract and functional (higher scope, higher in the tree), the same directionality observed in historical development (von Fintel, 1995; Roberts & Roussou, 2003; i.a.).

Finding the force: How children discern possibility and necessity modals

International audienceThis paper investigates when and how children figure out the force of modals: that possibility modals (e.g. can/might) express possibility, and necessity modals (e.g. must/have to), necessity. Modals raise a classic subset problem: given that necessity entails possibility, what prevents learners from hypothesizing possibility meanings for necessity modals? Three solutions to such subset problems can be found in the literature: the first is for learners to rely on downward-entailing environments (Gualmini and Schwarz 2009); the second is a bias for strong (here, necessity) meanings; the third is for learners to rely on pragmatic cues, stemming from the conversational context (Dieuleveut et al. 2019, Rasin and Aravind 2020).&nbsp; This paper assesses the viability of each of these solutions, by examining the modals used in speech to and by 2-year-old children, through a combination of corpus studies and experiments testing the guessability of modal force based on their context of use. Our results suggest that given the way modals are used in speech to children, the first solution is not viable, and the second unnecessary. Instead, we argue that the conversational context in which modals occur is highly informative as to their force, and sufficient, in principle, to sidestep the subset problem. Our child results further suggest an early mastery of possibility, but not necessity modals, and show no evidence for a necessity bias.</p