Children need to start learning English from a very young age in this fast globalizing world. The knowledge of the English language can assist in providing several opportunities for them in the future. It is also essential to know how very young children acquire a foreign language and which content and activities should be selected for their age. This study aimed to observe and describe the procedure of the language development of very young children. Researchers employed a descriptive case study design to portray and assess foreign language learning of two three-year-old twins’ grammar acquisition, vocabulary gains, and fluency in the early years of life (3-4/5). Besides the methods firmly associated with qualitative study and case studies, there were four sources of data collection: observation, audio-video recordings, and diary records. The central unit of the twins’ language development analysis was their utterances. The findings supported using a naturalistic environment where very young children could be exposed to the English language informally in everyday contexts and activities. This research can share its findings with education communities and very young children’s teachers to promote a new professional development model for fostering language development in very young learners’ classrooms, assessments, and curricula.
