Continuous approaches to measuring bilingualism have recently emerged as a means of understanding individual variation in lan-guage abilities. To date, limited information is available to assist in understanding the language abilities of bilingual children with Down syndrome (DS), who are specifically known to have a large variation in linguistic outcomes. Group studies in this population report that children exposed to two languages do not differ from their monolingual counterparts after considering age and non- verbal cognitive abilities, although no study to date has examined the relationship between the amount of exposure to one language and the linguistic abilities in the other language within this popula-tion. This study sought to identify whether exposure to an addi-tional language, specifically Welsh, predicted linguistic abilities in the majority language, in this case, English. Sixty-five children between the ages of 5;5–16;9 who had varied linguistic experiences completed a range of cognitive and linguistic assessments. Results from hierarchical regression analyses show that the amount of exposure to Welsh had no impact on language abilities in English, after controlling for non-verbal cognitive abilities, short-term mem-ory and socioeconomic status. This demonstrates that exposure to an additional language does not have a negative impact on lan-guage development, a finding that has important clinical and edu-cational implications.