Language Learning and Development ISSN: 1547-5441 (Print) 1547-3341 (Online) Journal homepage: https://www.tandfonline.com/loi/hlld20 Leaving Obligations Behind: Epistemic Incrementation in Preschool English Ailís Cournane & Ana Teresa Pérez-Leroux To cite this article: Ailís Cournane & Ana Teresa Pérez-Leroux (2020): Leaving Obligations Behind: Epistemic Incrementation in Preschool English, Language Learning and Development, DOI: 10.1080/15475441.2020.1738233 To link to this article: https://doi.org/10.1080/15475441.2020.1738233 Published online: 27 Apr 2020. Submit your article to this journal View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=hlld20 LANGUAGE LEARNING AND DEVELOPMENT https://doi.org/10.1080/15475441.2020.1738233 Leaving Obligations Behind: Epistemic Incrementation in Preschool English Ailís Cournanea and Ana Teresa Pérez-Lerouxb aDepartment of Linguistics, New York University, New York, New York, USA; bDepartments of Spanish & Portuguese and Linguistics, University of Toronto, Toronto, Ontario, Canada ABSTRACT Does language development drive language change? A common account of language change attributes the regularity of certain patterns to children’s learning biases. The present study examines these predictions for change-in -progress in the use of must in Toronto English. Historically, modal verbs like must start with root (deontic) meanings, eventually developing epistemic (probability) meanings in addition. Epistemic uses increase over successive generations, phasing out root uses (INCREMENTATION). The modal becomes unambiguously epistemic and eventually disappears from the language. Such cyclic changes are predictable and common across languages. To explore whether children contribute to incrementation and loss, we tested intuitions about must in preschoolers (n = 141) and adults (n = 29). In a picture-preference task (deontic vs. epistemic), children selected epistemic interpretations of ambiguous sentences (e.g., Michelle must swim) at higher rates than adults. Two context-based preference tasks tested children’s overall sensitivity to the presence of modals. We found sensitivity in deontic contexts. In epistemic contexts, where must is optional and functions like an evidential marker, we found little discrimination, and general avoidance of the modal. These results (epistemic overgeneration, must-avoidance) corre- spond to predictions of the incrementation hypothesis, suggesting children likely play an active role in language change, beyond well-known over- regularization processes. Introduction Languages change with time. Some changes appear both predictable and directional. What drives those changes? As far back as the 1880s, historical linguists speculated that the dynamic nature of child language development underlies regular language change (Paul, 1880, i.a.). More recently, theoreticians have posited that children introduce change by reinterpreting properties of the input (Hale, 1998; Lightfoot, 1979; Roberts & Roussou, 2003; Van Gelderen, 2011). This studyexploreswhetherchildrendrivechangeinonewell-studiedcaseofregularlanguage change: modal verbs. Modals allow speakers to express non-actuality. Modal meanings divide into two broad flavors. 1 ROOT modality includes abilities, goals, and obligations, among others. EPISTEMIC modality includes inferences from knowledge or evidence. We focus on must which, like many other modals verbs in English and other languages, is flavor-variable and can be interpreted as either root (1a) or epistemic (1b). CONTACT Ailís Cournane [email protected] Department of Linguistics, New York University, 10 Washington Pl, New York, NY 10003 1Root modality (Hoffmann, 1966) includes all non-epistemic meanings that attribute the possibility or necessity of the predicate to the subject of the verbal event. Deontic modality is one subtype of root modality. © 2020 Taylor & Francis Group, LLC 2 A. COURNANE AND A. T. PÉREZ-LEROUX (1) Penguin must eat a lot of fish a. … otherwise he will freeze. (Root: Obligation or Goal) b. … because he’s plump. (Epistemic: Inference) Interestingly, flavor-variable modals commonly change unidirectionally, from historically older root uses to newer epistemic ones (Bybee et al., 1994; Lightfoot, 1979; Traugott, 1989, 2006). The predictability of these diachronic processes begs for an inquiry into language transmission and the role of language acquisition. While the standard method in language acquisition is to measure the child against an adult norm (since Brown, 1973), full convergence is not the only possible outcome. Children might change the system as they learn it. Robust, regular diachronic patterns represent an optimal place to investigate the role of children in language change (Cournane, 2014, 2015, 2017). Standard methodology implicitly predicates the existence of a stable reference point – a target system of forms and meanings. However, language (and language input) is neither homogenous nor temporally stable (Kroch, 1989; Van Gelderen, 2011; Weinreich et al., 1968). Recent studies have tackled this issue directly, by examining how variability in the input affects the timetable and outcome of development, including the effect of phonetic variation in the formation of grammatical categories (Miller, 2012; Schmale et al., 2010), and to what extent prosodic variability affects children’s performance (Ettlinger & Zapf, 2011; Sundara et al., 2011). Artificial language studies show that child learners extract regular patterns from inconsistent input (Hudson Kam & Newport, 2009). A current line of work investigates how much noise can be tolerated before disrupting rule generalization (Hendricks et al., 2018; Schuler et al., 2016; Yang, 2016). In natural contexts, work on Nicaraguan Sign Language explores how younger learners introduce language systematicity (Cohort 2 and later; e.g., Senghas & Coppola, 2001). A separate literature studies to what extent children are able to mirror sociolinguistic patterns of variability. Some of this work explicitly assumes commu- nity-level directional patterns of generational change exist, but that child learners do not create them (Labov, 2001, 2007; Smith et al., 2013; i.a.). Finally, usage-based approaches to first language acquisition stress individual differences and non-homogeneity of input, arguing these are an “inconvenient truth” for generative approaches which standardly abstract away from variability (Kidd et al., 2018). Our focus is on the question of what role children might play in generating such variation (as opposed to only experiencing it) and in determining its directionality (in the case of regular cyclic historical changes). A perspective from the study of diachronic syntax holds that children play an active role in language change, as creators and selectors of the target of change (Lightfoot, 1979; Roberts & Roussou, 2003; Van Gelderen, 2011). While this is accepted for regularization processes (Fedzechkina et al., 2016; Hudson Kam & Newport, 2009), it has not yet been tested for cyclical changes (Van Gelderen, 2011), that is, an identified set of recurrent patterns that affect certain words, such as modals (Bybee et al., 1994) or negation (Jespersen, 1917; Van Gelderen, 2011). We assume that both children and languages are dynamic systems changing over time, and propose to test whether learner dynamics underlie the dynamics of language change in the case of modal verbs by extracting predictions from what is known from the diachronic modal cycle. English auxiliary modal verbs (e.g., can, will, might) derive from the past tense forms of West Germanic/Old English main verbs. Must was first recorded as a content verb with an ability/ permission meaning (cf. be able/allowed to)2 (2a). By Middle English, it was a flavor-variable auxiliary modal verb (Lightfoot, 1979; Visser, 1963), with primarily root usage (Traugott, 2006) (2b). A gradual shift toward epistemic uses is still in progress, most advanced in some varieties of English such as the one spoken in Toronto (Tagliamonte & D’Arcy, 2007) (2c). As one modal changes, historically newer forms take over older uses, like have to and got to in English, which are currently primarily used with root meanings that were previously associated with must (Fischer, 1994; Krug, 2000). The modal cycle is renewed over time with new words. The Toronto variety of 2In its history must strengthened from a possibility modal to a necessity modal, e.g., permission > obligation, a change not central to our current study (Yanovich, 2013). LANGUAGE LEARNING AND DEVELOPMENT 3 English is one where the use of have to, over must, increases sharply across age spans (preadoles- cents, adolescents, adults, and seniors); suggesting an advanced stage in the cycle for must. Preadolescent girls use have to for obligation meanings about 25% more than older women. The usage differences by age group are more extreme for males, namely, older men use more of old- fashioned must than modern have to. The preadolescent and adolescent groups in Tagliamonte and D’Arcy’s(2007) study are significantly different from each other, with usage rates varying by age group, a typical indicator of change-in-progress over time in a language.3 (2) Must in diachrony (based on Traugott, 2006; Oxford English Dictionary) ō (a) motev, past.m ste (b) most(e), must (c) must → → <O.E (400-1100CE) M.E. (1100-1500CE) Mod.E. (1500CE-Today) ~be able/permitted to obligation, (epistemic)