UC San Diego

Developmental Language Disorder (DLD) is characterized by a challenge in acquiring and using language. Vocabulary size is impacted, as adults with a history of DLD may experience a “vocabulary gap” in word knowledge, with fewer word representations stored in the mental lexicon. Furthermore, adults with a history of DLD may experience lexical access delays, with slower form-to-meaning mapping during processing for word recognition. For bilinguals, word representations are stored in an integrated lexicon and crosslexical interaction influences word identification dynamics. Evidence of crosslexical facilitation is found in cognate effects, whereby translation equivalents that share similar form are more accurately and quickly recognized than those with little to no overlap. Whether crosslexical processing dynamics are disrupted by DLD remains an open question. Thus, this current dissertation investigates the intersection of DLD and word representation/processing within a bilingual model for word recognition. Findings suggest that language differences between adult bilinguals with and without a history of DLD may be limited to aspects of word knowledge and processing, with similar metalinguistic strategies for word recognition. Chapter 1 provides an overview of bilingual word recognition dynamics and establishes a groundwork to make word recognition predictions based on participant-internal factors, such as language experience and a history of DLD, and task-internal ones, including form overlap between target words and translation equivalents. Chapter 2 establishes a relation between word recognition accuracy and language experience in typical bilingual adult. This relation is further investigated in Chapter 3, including an extension of investigations to bilingual adults with a history of DLD. Chapter 4 shifts from an investigation of word representation to word processing, detailing the relation between lexical access and language experience via button-press (overt response) and eye-gaze behavior (covert/subconscious response). Chapter 5 looks beyond the word identification system and seeks to explore the influence of higher-order processing, namely metalinguistic awareness, on word recognition. In conclusion, Chapter 6 summarizes and integrates findings from these studies to establish a baseline for understanding the impact of DLD on vocabulary during early adulthood for bilinguals, with potential future directions to fill gaps where current limitations lie.