The study examined heritage speaker grammars and to what extent they diverge with respect to grammatical gender from adult L2 learners. Results from a preference task involving code-mixed Determiner Phrases (DPs) and code-mixed copula constructions show a difference between these two types of operations. Heritage speakers patterned with the control group of L1 Spanish/L2 English speakers for the copula/agreement constructions but differed from the control group for the DP conditions. We argue that it may be the case that the two operations (concord versus agreement) are processed differently by heritage speakers and people raised monolingually. If this idea is on the right track, then it can be assumed that it is processing and not different underlying representations that are the cause of the differences among the groups. (Contains 2 tables and 4 figures.)