This qualitative study presents sociolinguistic characteristics of peer-talk of 44 children in a Mandarin-English-speaking preschool in Taiwan where English was taught as a foreign language (EFL). Key findings: teacher-dominated talk influences children's peer-talk; EFL and code-switching emerge in spontaneous peer-talk; children actively engage in EFL learning by using private speech for self-regulatory learning; children actively provide peer tutoring even though they are in the early stage of EFL learning; and language play creates emergent humor for children's verbal participation in the EFL classroom, offering a way for them to resist authoritative voices and thus transform EFL into a living language. (Contains 2 tables.)