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.

Effect of sex and dyad composition on speech and gesture development of singleton and twin children.

Children's early vocabulary shows sex differences - with boys having smaller vocabularies than age-comparable girls - a pattern that becomes evident in both singletons and twins. Twins also use fewer words than their singleton peers. However, we know relatively less about sex differences in early gesturing in singletons or twins, and also how singletons and twins might differ in their early gesture use. We examine the patterns of speech and gesture production of singleton and twin children, ages 0;10-to-3;4, during structured parent-child play. Boys and girls - singleton or twin - were similar in speech and gesture production, but singletons used a greater amount and diversity of speech and gestures than twins. There was no effect of twin dyad type (boy-boy, girl-girl, boy-girl) on either speech or gesture production. These results confirm earlier research showing close integration between gesture and speech in singletons in early language development, and further extend these patterns to twin children.

Harmonic cues for speech segmentation: a cross-linguistic corpus study on child-directed speech.

Previous studies on the role of vowel harmony in word segmentation are based on artificial languages where harmonic cues reliably signal word boundaries. In this corpus study run on the data available at CHILDES, we investigated whether natural languages provide a learner with reliable segmentation cues similar to the ones created artificially. We observed that in harmonic languages (child-directed speech to thirty-five Turkish and three Hungarian children), but not in non-harmonic ones (child-directed speech to one Farsi and four Polish children), harmonic vowel sequences are more likely to appear within words, and non-harmonic ones mostly appear across word boundaries, suggesting that natural harmonic languages provide a learner with regular cues that could potentially be used for word segmentation along with other cues.