The purpose of this study is to describe the second language learning experience of a young Korean-English learner living in the UK and attending primary school, but with very limited English ability at the start of the study (two months after her arrival). The study focused on the child's home reading activities and play at home from a Vygotskian sociocultural perspective, exploring family scaffolding, motivation, learning opportunities, and appropriation of English as a second language (ESL) in developing her communicative competence. The study provides thick descriptions of the Korean child's utterances in the informal context. The data used in the study include six different types of home reading and other six play activities, mother's observational journal as a participant and researcher, the child's English writing, and teacher interviews about her settlement in the classroom. The study documented family scaffolding practices for children's ESL learning. Through home reading activities, the monolingual grandmother's encouragement and questioning contributed to appropriation of vocabulary in both L1 and L2 via self-regulation. Mother's instructional interactions activated the child's ZPD and led to voluntary role-plays among siblings, which contributed to the children's confidence in ESL use through mutual scaffolding. The children's willingness to join in different types of play at home also fostered mutual scaffolding for English use and increased learning opportunities within their ZPD, as seen for example in imitation or self-regulatory private speech use. Play props served to promote communicative competence. Further research is recommended about ESL children in mainstream schools in the U.K. and their socialization process in mastering English.