Children's Acquisition of the English Past-Tense: Evidence for a Single-Route Account From Novel Verb Production Data

Analogy is indispensable but rule is a must: Insights from Turkish

Inflectional morphology provides a unique platform for a discussion of whether morphological productivity is rule-based or analogy-based. The present study testing 140 children (range = 29 to 97 months; M(SD) = 64.1(18.8)) on an elicited production task investigated the acquisition of the irregular distribution in the Turkish aorist. Results suggested that to discover the allomorphs of the Turkish aorist, children initially carried out similarity comparisons between analogous exemplars, which helped them tap into phonological features to induce generalizations for regulars and irregulars. Thereafter to tackle the irregularity, children entertained competing hypotheses yielding overregularizations and irregularizations. While the trajectory of overregularizations implicated the gradual formulation of an abstraction based on type-frequency, irregularizations suggested both intrusion of analogous exemplars and children's attempts to default to an erroneous micro-generalization. Our findings supported a model of morphological learning that is driven by analogy at the outset and that invokes rule-induction in later stages.

The nature and causes of children's grammatical difficulties: Evidence from an intervention to improve past tense marking in children with down syndrome

Children with language learning difficulties frequently display problems learning grammar. One such group are children with Down syndrome. This study evaluates the effectiveness of an intervention to teach the use of the regular simple past tense to children with Down syndrome. Trained teaching assistants delivered the intervention for 20 minutes per day for 10 weeks. We conducted a Randomised Controlled Trial, with a waiting list control design in which the Intervention group (N = 26) received the intervention immediately, while the delayed intervention group (N = 26) received the intervention later. Immediately following the intervention, the intervention group showed significantly larger gains in the use of regular simple past tense forms (d = 1.63 on a composite measure of simple past tense formation) as well as generalisation to verbs not explicitly taught. In addition, following the intervention children made overregularisation errors by incorrectly using regular simple past tense marking for irregular verbs; such errors support the claim that children had acquired generative knowledge underlying past tense marking. The delayed intervention control group showed identical benefits from the intervention when they received it, and the gains shown by the intervention group were maintained at follow up testing. This study shows that children with Down syndrome, who display severe language difficulties can be taught to use simple past tense marking. The theoretical and applied implications of these findings for understanding the nature, causes and treatments of children's language difficulties are discussed. This article is protected by copyright. All rights reserved.

Production of Inflected Novel Words in Older Adults With and Without Dementia

While cognitive changes in aging and neurodegenerative disease have been widely studied, language changes in these populations are less well understood. Inflecting novel words in a language with complex inflectional paradigms provides a good opportunity to observe how language processes change in normal and abnormal aging. Studies of language acquisition suggest that children inflect novel words based on their phonological similarity to real words they already know. It is unclear whether speakers continue to use the same strategy when encountering novel words throughout the lifespan or whether adult speakers apply symbolic rules. We administered a simple speech elicitation task involving Finnish-conforming pseudo-words and real Finnish words to healthy older adults, individuals with mild cognitive impairment, and individuals with Alzheimer's disease (AD) to investigate inflectional choices in these groups and how linguistic variables and disease severity predict inflection patterns. Phonological resemblance of novel words to both a regular and an irregular inflectional type, as well as bigram frequency of the novel words, significantly influenced participants' inflectional choices for novel words among the healthy elderly group and people with AD. The results support theories of inflection by phonological analogy (single-route models) and contradict theories advocating for formal symbolic rules (dual-route models).

Sensitivity to Inflectional Morphemes in the Absence of Meaning: Evidence from a Novel Task

A number of studies in different languages have shown that speakers may be sensitive to the presence of inflectional morphology in the absence of verb meaning (Caramazza et al. in Cognition 28(3):297-332, 1988; Clahsen in Behav Brain Sci 22(06):991-1013, 1999; Post et al. in Cognition 109(1):1-17, 2008). In this study, sensitivity to inflectional morphemes was tested in a purposely developed task with English-like nonwords. Native speakers of English were presented with pairs of nonwords and were asked to judge whether the two nonwords in each pair were the same or different. Each pair was composed either of the same nonword repeated twice, or of two slightly different nonwords. The nonwords were created taking advantage of a specific morphophonological property of English, which is that regular inflectional morphemes agree in voicing with the ending of the stem. Using stems ending in /l/, thus, we created: (1) nonwords ending in potential inflectional morphemes, vɔld, (2) nonwords without inflectional morphemes, vɔlt, and (3) a phonological control condition, vɔlb. Our new task endorses some strengths presented in previous work. As in Post et al. (2008) the task accounts for the importance of phonological cues to morphological processing. In addition, as in Caramazza et al. (1988) and contrary to Post et al. (2008), the task never presents bare-stems, making it unlikely that the participants would be aware of the manipulation performed. Our results are in line with Caramazza et al. (1988), Clahsen (1999) and Post et al. (2008), and offer further evidence that morphologically inflected nonwords take longer to be discriminated compared to uninflected nonwords.