Melissa Kline

Factors Facilitating Implicit Learning: The Case of the Sesotho Passive

Researchers have long debated the mechanisms underlying the learning of syntactic structure. Of significant interest has been the fact that passive constructions appear to be learned earlier in Sesotho than English. This paper provides a comprehensive, quantitative analysis of the passive input Sesotho-speaking children hear, how it differs from English input, and the implications for learning the passive. The findings indicate that the more frequent use of both the passive and the by-phrase in Sesotho child-directed speech, in conjunction with the non-ambiguous passive morpheme, may together facilitate earlier access to thematic roles (agent, patient), thereby promoting early implicit learning of the passive. The implications for the acquisition of syntactic structure more generally are discussed.

The distribution of passives in spoken Sesotho

A previous study of passive constructions has suggested that these are much more frequent in Sesotho than in English spontaneous speech (Demuth, 1989). This has raised a number of questions regarding the possible effects of the input on the apparently earlier acquisition of passives in Sesotho. This paper explores the distribution of passives in Sesotho child-directed speech. It aims to provide a more thorough investigation of the grammatical, lexical and discourse contexts in which the passive is used. The findings confirm that passives occur in approximately 4% of utterances directed at 2–3-year olds. Many of these are full (rather than truncated) passives, most occurring with actional verbs that show active/passive alternations. Many passives are also questions/clarifications about past events. The implications for language acquisition are discussed.

Linking Language and Events: Spatiotemporal Cues Drive Children’s Expectations About the Meanings of Novel Transitive Verbs

ABSTRACT How do children map linguistic representations onto the conceptual structures that they encode? In the present studies, we provided 3–4-year-old children with minimal-pair scene contrasts in order to determine the effect of particular event properties on novel verb learning. Specifically, we tested whether spatiotemporal cues to causation also inform children’s interpretation of transitive verbs either with or without the causal/inchoative alternation (She broke the lamp/the lamp broke). In Experiment 1, we examined spatiotemporal continuity. Children saw scenes with puppets that approached a toy in a distinctive manner, and toys that lit up or played a sound. In the causal events, the puppet contacted the object, and activation was immediate. In the noncausal events, the puppet stopped short before reaching the object, and the effect occurred after a short pause (apparently spontaneously). Children expected novel verbs used in the inchoative transitive/intransitive alternation to refer to spatiotemporally intact causal interactions rather than to “gap” control scenes. In Experiment 2, we manipulated the temporal order of sub-events, holding spatial relationships constant, and provided evidence for only one verb frame (either transitive or intransitive). Children mapped transitive verbs to scenes where the agent’s action closely preceded the activation of the toy over scenes in which the timing of the two events was switched, but did not do so when they heard an intransitive construction. These studies reveal that children’s expectations about transitive verbs are at least partly driven by their nonlinguistic understanding of causal events: children expect transitive syntax to refer to scenes where the agent’s action is a plausible cause of the outcome. These findings open a wide avenue for exploration into the relationship between children’s linguistic knowledge and their nonlinguistic understanding of events.

Syntactic generalization with novel intransitive verbs

To understand how children develop adult argument structure, we must understand the nature of syntactic and semantic representations during development. The present studies compare the performance of children aged 2;6 on the two intransitive alternations in English: patient (Daddy is cooking the food/The food is cooking) and agent (Daddy is cooking). Children displayed abstract knowledge of both alternations, producing appropriate syntactic generalizations with novel verbs. These generalizations were adult-like in both flexibility and constraint. Rather than limiting their generalizations to lexicalized frames, children produced sentences with a variety of nouns and pronouns. They also avoided semantic overgeneralizations, producing intransitive sentences that respected the event restrictions and animacy cues. Some generated semantically appropriate agent intransitives when discourse pressure favored patient intransitives, indicating a stronger command of the first alternation. This was in line with frequency distributions in child-directed speech. These findings suggest that children have early access to representations that permit flexible argument structure generalization.

Partial Truths: Adults Choose to Mention Agents and Patients in Proportion to Informativity, Even If It Doesn’t Fully Disambiguate the Message

How do we decide what to say to ensure our meanings will be understood? The Rational Speech Act model (RSA; Frank & Goodman, 2012) asserts that speakers plan what to say by comparing the informativity of words in a particular context. We present the first example of an RSA model of sentence-level (who-did-what-to-whom) meanings. In these contexts, the set of possible messages must be abstracted from entities in common ground (people and objects) to possible events (Jane eats the apple, Marco peels the banana), with each word contributing unique semantic content. How do speakers accomplish the transformation from context to compositional, informative messages? In a communication game, participants described transitive events (e.g., Jane pets the dog), with only two words, in contexts where two words either were or were not enough to uniquely identify an event. Adults chose utterances matching the predictions of the RSA even when there was no possible fully “successful” utterance. Thus we show that adults’ communicative behavior can be described by a model that accommodates informativity in context, beyond the set of possible entities in common ground. This study provides the first evidence that adults’ language production is affected, at the level of argument structure, by the graded informativity of possible utterances in context, and suggests that full-blown natural speech may result from speakers who model and adapt to the listener’s needs.

Young children choose informative referring expressions to describe the agents and patients of transitive events

A key component of most models of pragmatics is that speakers consider more than one way of conveying a message, and how informative each version is in context. Theories of pragmatics, and particularly pragmatic development, are hampered by the fact that while we can often observe what a participant does (either as a speaker or a listener), we can rarely observe the choices they consider. Here, we focus on the problem that remains once two alternative utterances are available: selecting the most informative one. By providing 3-6 year old children with a choice between transitive sentences that drop either an uninformative argument (i.e. one that can be directly recovered from the visual context) or an informative one, we can directly test their ability to select between alternate ways of conveying the same message, abstracting away from the many other processes required to produce a multi-word expression. While 3 year olds select between these alternatives at chance (a pattern which, based on control version, may be partially due to task demands), we find clear evidence that children aged 4 and older preferentially select the more informative option. This result shows that (1) childrens awareness of informativity contrasts extends to sentence-level messages, not just object referent selection and (2) directly testing the development of specific cognitive abilities theorized to be involved in pragmatic communication can both clarify and constrain our theories of language development.