In monolingual (L1) acquisition, children produce target-like subject-verb agreement early in development both Spanish (Grinstead 1998) and English (Guasti 2002). However, heritage simultaneous bilinguals (2L1) child second language acquirers (L2), morphology shows variability (Goldin 2020; Herschensohn & Stevenson 2005) due to age of acquisition (AoA) effects. Lexical frequency is another ...