This study used lexical tasks to examine associations between languages, tasks, and age in bilingual children with primary language impairment. Participants (n = 41, mean age 8;8 years) lived in the United States, spoke primarily Spanish (L1) at home and English (L2) at school, and were identified with moderate to severe impairments in both languages. A total of eight tasks (four in each language) measured breadth of vocabulary knowledge (receptive and expressive vocabulary) and aspects of lexical processing (rapid automatic naming and nonword repetition). Correlational analyses revealed older children outperformed younger children on lexical tasks in L2 but not L1, as well as relative L2 dominance for most individuals and tasks. Positive associations were found between languages on processing-based tasks but not vocabulary measures. Findings were consistent with literature on typical bilingual learners, albeit with a notable increased risk of plateau in L1 growth. Results are interpreted within a Dynamic Systems framework.