This dissertation aimed to investigate the relationship between language dominance and the top-down effect of prior knowledge in statistical word learning tasks among Spanish and English speakers. Through four studies, it examined the facilitation effect of English and Spanish words on statistical learning, the potential interference of top-down cues from English and Spanish words, and the domain generality of statistical word learning by comparing auditory and visual modalities.While no definitive conclusions were reached regarding the interaction between top-down effects and language dominance, a notable finding emerged: Language dominance (as measured by Bilingual Language Profile scores) and language proficiency (as measured by English and Spanish LexTALE tests) were the most consistent predictors of performance across most conditions. Unbalanced English dominance and higher English LexTALE scores compared to Spanish LexTALE scores were consistently associated with better performance on nearly all statistical word learning tasks, regardless of the language of the Known-Word (English or Spanish). These results underscore the importance of using more objective and robust measures of language background to better understand the cognitive mechanisms underlying statistical learning abilities in adults. Additionally, further research is needed to clarify the role of top-down effects in statistical word learning among Spanish and English speakers.