Morphological processing of Turkish derived words: Does bilingualism affect the processing route?

It has been suggested that native speakers may develop different processing patterns in their first language as they become proficient second language users. While most of the studies are conducted with heritage speakers whose first language is the minority language in the society they live in, the number of studies that investigate first language as the majority language remains scarce. These studies have shown that high proficiency in a second language can influence first language processing even in the majority language context (van Hell & Dijkstra, 2002; Uygun & Gürel, 2020). The aim of the present study is to explore how proficient Turkish-English late bilinguals process Turkish derived words. 61 monolingual Turkish speakers and 46 proficient Turkish-English late bilingual speakers were tested via a masked priming experiment. The stimuli consisted of (i) transparent words (dalga “wave”, dal “dive” and –ga is the derivational suffix), (ii) opaque words (karga “crow”, kar “snow” but –ga does not function as a derivational suffix), and (iii) form/control words (devre “period”, dev “giant”, –re is not an existing derivational suffix). The results showed no significant group differences in the morphological processing of Turkish derived words. While both monolingual and bilingual speakers employed decomposition for transparent and opaque words, no morphological parsing was observed for the form/control words. These results suggest that not only monolingual but also bilingual speakers decompose derived words regardless of their transparency, suggesting that high proficiency in a second language does not affect the morphological processing route of the first language.