Artificial language learning of morphological rules in children with developmental language disorders

Description

Humans can productively extend their linguistic knowledge to create and understand novel linguistic expressions. The Tolerance Principle (Yang, 2016) provides a framework for understanding linguistic productivity in typical development. According to this principle, morphological rules (e.g., ‘add -s’ to form a plural) are acquired when the cost of memorizing the exceptions does not outweigh the efficiency of rule application. Although this principle has been investigated in typical language development, its application to children with Developmental Language Disorder (DLD)—who often struggle in the morphosyntactic domain—has not yet been explored.
We aimed to investigate whether the tolerance principle predicted the acquisition of morphological rules in 53 children with DLD, by comparing them to 52 typically-developing (TD) peers and 50 adults. Participants were exposed to singular and plural pseudowords
(e.g., [zɔmu]/[zɔmupɐ]) using a controlled artificial language learning paradigm under two conditions: one favoring rule acquisition (6 regular types, 4 irregular types—6R4I) and one that did not (4 regular types, 6 irregular types—4R6I), with equal token frequencies between conditions. Participants' plural generalizations were tested with 24 novel words. Logistic mixed-effects regression revealed that TD children were much more likely to use regular than irregular suffixes in the 6R4I condition (98% regular), but not in the 4R6I condition (38% regular). In contrast, for both children with DLD (6R4I: 56%; 4R6I: 62%) and adult
participants (6R4I: 61%; 4R6I: 38%), proportions of regular suffixes were not significantly different from 50%, nor between the two conditions.
The results suggest that TD children learn a morphological rule only when supported by distributional evidence, as predicted by the tolerance principle. In contrast, children with DLD failed to generalize the regular suffix, even under favourable conditions. Despite their differences in the use of the regular suffix, children with DLD produced a similar proportion of learned suffixes as TD children, suggesting specific difficulties in abstracting morphological rules. Likewise, adult participants were not sensitive to the experimental manipulation, which may indicate the use of type-driven statistical learning. Our findings underscore the significance of age and distributional factors in acquiring morphological rules and help characterize morphological learning in children with DLD.

Period	25 Nov 2024
Event title	6th Students Meeting of Mind-Brain College of ULisboa
Event type	Conference
Location	Lisbon, PortugalShow on map
Degree of Recognition	Local