Testing a computational model of causative overgeneralizations: Child judgment and production data from English, Hebrew, Hindi, Japanese and K'iche'.

How do language learners avoid the production of verb argument structure overgeneralization errors ( *The clown laughed the man c.f. The clown made the man laugh), while retaining the ability to apply such generalizations productively when appropriate? This question has long been seen as one that is both particularly central to acquisition research and particularly challenging. Focussing on causative overgeneralization errors of this type, a previous study reported a computational model that learns, on the basis of corpus data and human-derived verb-semantic-feature ratings, to predict adults' by-verb preferences for less- versus more-transparent causative forms (e.g., * The clown laughed the man vs The clown made the man laugh) across English, Hebrew, Hindi, Japanese and K'iche Mayan. Here, we tested the ability of this model (and an expanded version with multiple hidden layers) to explain binary grammaticality judgment data from children aged 4;0-5;0, and elicited-production data from children aged 4;0-5;0 and 5;6-6;6 ( N=48 per language). In general, the model successfully simulated both children's judgment and production data, with correlations of r=0.5-0.6 and r=0.75-0.85, respectively, and also generalized to unseen verbs. Importantly, learners of all five languages showed some evidence of making the types of overgeneralization errors - in both judgments and production - previously observed in naturalistic studies of English (e.g., *I'm dancing it). Together with previous findings, the present study demonstrates that a simple learning model can explain (a) adults' continuous judgment data, (b) children's binary judgment data and (c) children's production data (with no training of these datasets), and therefore constitutes a plausible mechanistic account of the acquisition of verbs' argument structure restrictions.

The acquisition of noun inflection in Northern Pame (Xi'iuy): Comparing whole word and minimal word accounts.

The study used naturalistic data on the production of nominal prefixes in the Otopamean language Northern Pame (autonym: Xi'iuy) to test Whole Word (constructivist) and Minimal Word (prosodic) theories for the acquisition of inflection. Whole Word theories assume that children store words in their entirety; Minimal Word theories assume that children produce words as binary feet. Northern Pame uses obligatory portmanteaux prefixes to inflect nouns for class, number, animacy and possessor. Singular nouns constitute 90 percent of the nouns that the children hear and yet all five two-year-old children frequently omitted the singular noun prefixes, but produced the low frequency noun suffixes for dual and animate plural. Neither the children's production of the noun-class prefixes nor their prefix overextensions correlated with the adult type and token frequencies of production. Northern Pame children constructed Minimal Words that contain binary feet and disfavor the production of initial, extrametrical prefixes.

Documenting the acquisition of indigenous languages.

The outstanding property of human language is its diversity, and yet acquisition data is only available for three percent of the world's 6000+ spoken languages. Due to the rapid pace of language loss, it may not be possible to document how children acquire half of the world's indigenous languages in as little as two decades. This loss permanently diminishes the scope of acquisition theory by removing its empirical base. In the face of pervasive language loss, the question of how best to document the language of the last children to acquire indigenous languages assumes critical importance. A collaborative effort by researchers is required to identify the most efficient procedures for documenting children's language, and share them worldwide. This paper makes the case for documenting diversity and outlines steps needed to accomplish this goal.

The crosslinguistic acquisition of sentence structure: Computational modeling and grammaticality judgments from adult and child speakers of English, Japanese, Hindi, Hebrew and K'iche'.

This preregistered study tested three theoretical proposals for how children form productive yet restricted linguistic generalizations, avoiding errors such as *The clown laughed the man, across three age groups (5-6 years, 9-10 years, adults) and five languages (English, Japanese, Hindi, Hebrew and K'iche'). Participants rated, on a five-point scale, correct and ungrammatical sentences describing events of causation (e.g., *Someone laughed the man; Someone made the man laugh; Someone broke the truck; ?Someone made the truck break). The verb-semantics hypothesis predicts that, for all languages, by-verb differences in acceptability ratings will be predicted by the extent to which the causing and caused event (e.g., amusing and laughing) merge conceptually into a single event (as rated by separate groups of adult participants). The entrenchment and preemption hypotheses predict, for all languages, that by-verb differences in acceptability ratings will be predicted by, respectively, the verb's relative overall frequency, and frequency in nearly-synonymous constructions (e.g., X made Y laugh for *Someone laughed the man). Analysis using mixed effects models revealed that entrenchment/preemption effects (which could not be distinguished due to collinearity) were observed for all age groups and all languages except K'iche', which suffered from a thin corpus and showed only preemption sporadically. All languages showed effects of event-merge semantics, except K'iche' which showed only effects of supplementary semantic predictors. We end by presenting a computational model which successfully simulates this pattern of results in a single discriminative-learning mechanism, achieving by-verb correlations of around r = 0.75 with human judgment data.

The Acquisition of Directionals in Two Mayan Languages.

We use the comparative method of language acquisition research in this article to investigate children's expression of directional clitics in two Eastern Mayan languages - K'iche' and Mam (Pye and Pfeiler, 2014; Pye, 2017). The comparative method in historical linguistics reconstructs the grammatical antecedents of modern languages and traces the evolution of each linguistic feature (Paul, 1889; Campbell, 1998). This history informs research on language acquisition by demonstrating how phonological and morphological features interact in the evolution of new uses for common inherited traits. Children acquiring modern languages must learn the arbitrary constraints imposed on their language by its history.

The comparative method of language acquisition research: a Mayan case study.

This article demonstrates how the Comparative Method can be applied to cross-linguistic research on language acquisition. The Comparative Method provides a systematic procedure for organizing and interpreting acquisition data from different languages. The Comparative Method controls for cross-linguistic differences at all levels of the grammar and is especially useful in drawing attention to variation in contexts of use across languages. This article uses the Comparative Method to analyze the acquisition of verb suffixes in two Mayan languages: K'iche' and Yucatec. Mayan status suffixes simultaneously mark distinctions in verb transitivity, verb class, mood, and clause position. Two-year-old children acquiring K'iche' and Yucatec Maya accurately produce the status suffixes on verbs, in marked distinction to the verbal prefixes for aspect and agreement. We find evidence that the contexts of use for the suffixes differentially promote the children's production of cognate status suffixes in K'iche' and Yucatec.

The poverty of the Mayan stimulus.

Poverty of the stimulus (POS) arguments have instigated considerable debate in the recent linguistics literature. This article uses the comparative method to challenge the logic of POS arguments. Rather than question the premises of POS arguments, the article demonstrates how POS arguments for individual languages lead to a reductio ad absurdum as POS arguments from genetically related languages are compared. Comparison leads to different contradictions for poverty of the negative stimulus (PONS) and poverty of the positive stimulus (POPS) arguments. Comparing PONS arguments leads to the conclusion that Universal Grammar contains language-specific versions of linguistic rules. Comparing POPS arguments leads to the conclusion that Universal Grammar may supply knowledge that is ungrammatical in the target language. The reductio shows that universal principles of grammar cannot be established on the basis of POS arguments from a single language.

Semantic deficits in children with language impairments: issues for clinical assessment.

Children with language impairments demonstrate a broad range of semantic difficulties, including problems with new word acquisition, storage and organization of known words, and lexical access/ retrieval. Unfortunately, assessments of children's semantic skills are often limited to measures of receptive and expressive vocabulary size. As a result, the semantic deficits of these children may not receive the attention they need. This article explores the word-learning, lexical storage, and lexical access skills of children with language impairments and the theories that account for their performance. Our review culminates with specific recommendations for speech-language pathologists to improve the breadth of their semantic assessments.