||The study investigated the relation between dynamic assessment, specifically a morpheme induction task (MIT), and parent ratings of children's language learning aptitude. Dynamic assessment may be an effective tool for testing bilingual children and a positive relationship with parent ratings would help confirm this finding. Secondly, the study aimed to investigate which factors affected performance on the MIT (age, language exposure, vocabulary level, and short-term memory). Twenty-six 5-6-year-old Spanish-English bilingual children and their parents participated. Results found no significant relationship between the MIT and parent ratings of children's language learning aptitude. MIT performance was related to age, language exposure, and short-term memory. Supplemental scoring schemes for the MIT showed different relations among variables. Different error types on the MIT were related to short-term memory, age, and language exposure at various levels. This dynamic assessment was affected by variables besides language abilities.