Purpose Identifying children with primary or specific language impairment (LI) in languages other than English continues to present a diagnostic challenge. This study examined the utility of English and Spanish nonword repetition (NWR) to identify children known to have LI. Method Participants were 4 groups of school-age children (N = 187). There were 2 typically developing groups: proficient Spanish-English sequential bilinguals and monolingual English speakers. There were 2 groups of children with LI, one Spanish-English and the other monolingual English speakers. Children participated in both English and Spanish NWR. Results Children’s NWR performance was significantly correlated across languages. In English NWR, the 2 groups with LI had lower accuracy at the longest syllable length than the 2 typically developing groups. In Spanish NWR, monolingual children with LI had lower repetition accuracy than bilingual children with LI and typical monolingual children, with all 3 groups outperformed by the typical bilingual group. Likelihood ratios indicated adequate diagnostic power only for English NWR in ruling out the typical bilingual children as showing LI. Conclusion The results demonstrate that NWR performance relies on the dual influences of LI and native language experience. However, it remains possible that NWR is useful in a composite marker for LI.