Metalinguistic skills may develop differently in multilingual and monolingual children. This study investigated effects of immersion in Cherokee as a second language on young children's (4;5-6;1) skills of noticing morphological forms/patterns in English, their first language, by comparing English past tense skills on two nonword and two real-word tasks between a Cherokee immersion group (N = 10) and an English-medium comparison group (N = 13). Only past finiteness (irregular forms plus overregularizations) on a real-word sentence imitation task was significantly different, with the Cherokee group performing better. The children learning Cherokee as a second language were progressing as well as their monolingual peers on English past tense marking and in one area had developed increased attention to productive morphological patterns.