The Afro-Hispanic creole, Palenquero, has been spoken (together with Spanish) in the village of San Basilio de Palenque, Colombia, for centuries. Until recently, Palenquero was endangered due to prejudice, but language revitalization efforts are underway, and younger speakers are learning Palenquero, but with little reinforcement out of school. The school instruction involves no grammatical explanations, almost no student production, or critical feedback. Adult speakers usually do not address younger speakers in Palenquero, thus leaving school-acquired forms suspended without reinforcement. This represents a unique scenario of heritage acquisition of a language with no bidirectional communication between younger and adult speakers. The present study focuses on the use of preverbal particles and prenominal plural marker by heritage speakers of Palenquero before and after explicit instruction. Communication activities explicitly presented the prenominal plural ma and preverbal particles, such as zero morpheme (simple present), asé (habitual), ta (progressive), a (perfective/simple past) and tan (future). Participants performed better at the post-test and results suggest that explicit explanation of grammatical rules, practice, repetition, and corrective feedback improved the usage of ma and tan. This result lines up with previous studies that posit the amount of time and exposure that learners need in order to acquire complex morphology.