Cognitive predictors of individual differences in language acquisition

Blake, Ashley R ORCID: 0000-0001-5963-9632 (2024). Cognitive predictors of individual differences in language acquisition. University of Birmingham. Ph.D.

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Abstract

There are vast individual differences in the way in which people acquire, process and use language. While most people learn their native language with ease, some people have difficulty with understanding and producing language in their day-to-day lives, a condition known as Developmental Language Disorder (DLD). Research to date has focused on cognitive and linguistic difficulties associated with DLD, but the underlying causes are not well-understood. A series of empirical studies were conducted with the objective of developing a deeper understanding regarding the interrelationship between cognitive abilities and language in children and adults, with and without DLD. There are two novel approaches to this research, firstly, the speed of automatization is explored using the Multiple-trial Tower of Hanoi paradigm, showing that automatization is relevant to language in children with DLD, and LT and DLD adults. Secondly, this thesis investigates the role of (foreign) language aptitude/analytic ability, with results suggesting that language aptitude is relevant to linguistic outcomes in language typical (LT) children and adults, with and without DLD. The overall results presented in this programme of research suggest that specific cognitive abilities are important for language. In children with DLD (study one), a cumulative risk model is presented, demonstrating the combinatory effects of nonverbal IQ, working memory, and speed of automatization. Study two investigates language and cognition in adulthood, showing that language aptitude is relevant to linguistic outcomes in adults with and without DLD. There are small to no differences in other cognitive abilities assessed in this study, yet the results show that adults with DLD require more time to process linguistic and non-linguistic tasks. Study three demonstrates that analogical reasoning is a key predictor of language in LT children and children with DLD. Lastly, a key relationship emerges between nonverbal intelligence and grammar, challenging the widely accepted view that grammar develops purely implicitly. Language difficulties have been studied since the 19th century, and although great strides have been made in gaining a deeper understanding of DLD, there is still much to learn. Collectively, the results from the studies detailed in this thesis provide evidence that individuals with DLD process language differently to their LT peers and show that certain cognitive abilities support language in DLD.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):