The competition–compensation account of developmental language disorder

Abstract

Children with developmental language disorder (DLD) regularly use the bare form of verbs (e.g., dance) instead of inflected forms (e.g., danced). We propose an account of this behavior in which processing difficulties of children with DLD disproportionally affect processing novel inflected verbs in their input. Limited experience with inflection in novel contexts leads the inflection to face stronger competition from alternatives.Competition is resolved through a compensatory behavior that involves producing a more accessible alternative: in English, the bare form. We formalize this hypothesis within a probabilistic model that trades off context-dependent versus independent processing. Results show an over-reliance on preceding stem contexts when retrieving the inflection in a model that has difficulty with processing novel inflected forms. We further show that following the introduction of a bias to store and retrieve forms with preceding contexts, generalization in the typically developing (TD) models remains more or less stable, while the same bias in the DLD models exaggerates difficulties with generalization. Together, the results suggest that inconsistent use of inflectional morphemes by children with DLD could stem from inferences they make on the basis of data containing fewer novel inflected forms. Our account extends these findings to suggest that problems with detecting a form in novel contexts combined with a bias to rely on familiar contexts when retrieving a form could explain sequential planning difficulties in children with DLD.

Development of sensitivity to beat gesture and contrastive accenting in support of word learning in early childhood in boys and girls

“…By comparison, the results of the current study show that, at age 3, boys leverage beat gesture to enhance their learning of novel words with contrasting meanings to the point that it is comparable to that of girls, whereas by age 4–5 years, boys no longer do so. These findings parallel findings for children with developmental language disorder, which disproportionately affects boys, showing that they rely on declarative memory to compensate for differences in procedural memory (Ullman & Pierpont, 2005), allowing them to learn novel inflected verbs effectively (Harmon et al, 2022). Thus, these sex differences in the impact of beat gesture may have been influenced by sex differences in word learning favoring girls in early childhood (Lange et al, 2016).…”

MOSAIC+: A Crosslinguistic Model of Verb‐Marking Errors in Typically Developing Children and Children With Developmental Language Disorder

“…A second possibility is that greater defaulting reflects a deficit in word learning and paradigm building. According to this view, greater defaulting reflects an underlying deficit in children's ability to learn low‐frequency forms and morphological patterns that leaves those with DLD more susceptible to competition from high‐frequency forms of the verb (see Harmon et al., 2023, for an account of deficits in past‐tense marking along these lines). And a third possibility is that greater defaulting reflects a deficit in children's ability to process long‐distance dependencies that differentiate between contexts that require lower‐ and higher‐frequency forms.…”

Building a unified model of the Optional Infinitive Stage: Simulating the cross-linguistic pattern of verb-marking error in typically developing children and children with Developmental Language Disorder

“…A second possibility is that greater defaulting reflects a deficit in word learning which has knock-on effects on paradigm building. According to this view, greater defaulting reflects an underlying deficit in the ability to learn low frequency forms and hence more productive morphological patterns, which leaves the child with DLD more susceptible to competition from high frequency forms (see Harmon, Barak, Shafto, Edwards, & Feldman, 2022, for an account of deficits in past tense marking along these lines). A third possibility is that greater defaulting reflects a deficit in the ability to process long-distance dependencies that differentiate between contexts that require lower and higher frequency forms.…”