Bootstrapping Word Order in Down Syndrome: Turkish Psycholinguistic Study

Down syndrome (DS) is a genetic condition resulting in problems with hearing, oral-motor, cognitive, social, prelinguistic and early nonverbal communication abilities. Language is one of the most severely compromised areas of cognitive functioning. It is essential to better understand how individuals with DS perceive, process, and learn their native language to develop effective intervention strategies. The current study seeks to contribute to this understanding, focusing on whether individuals with DS aged between 1 to 20 years learning Turkish show sensitivity to cues to the basic word order of their native language, which typically developing (TD) children are known to recognize at 7 months of age (Gervain et al. 2008). Particularly, TD infants identify frequent words as grammatical functors (e.g., articles, prepositions, pronouns such as the, on, up, he, it etc.) and use this frequency information to bootstrap the relative order of functors and content words in their native language. By utilizing an online version of the head-turn preference paradigm (HPP) which is the first implementation of a gaze-contingent using an online platform to an artificial language learning experiment similar to the one used in the original study (Gervin et al. 2008), we assessed whether individuals with DS show a similar sensitivity to the basic word order of their native language. Using this online paradigm with an atypically developing population is a further methodological challenge that our study addressed. Our results show that Turkish individuals with DS preferred i.e., showed longer looking times to, frequent final test items, as predicted, reflecting the function-word final order of Turkish. This result suggests that individuals with DS may be able to exploit some of the basic cues to the grammar of their native language and have better language perception and comprehension skills than previously believed. Keywords: Down Syndrome, Language Acquisition, Frequency-Based Bootstrapping, Word Order, Gaze-Contingent, Head-Turn Preference Procedure Online