Beginning to learn another language in early childhood is commonly considered an advantage for time gains for improving language skills and structuring the mind for subsequent learning. Teachers and parents who want to prepare children better for future professions and for life in the new world order express concerns and questions about the optimal time for introducing at least one other language. This study addresses the concerns about when to start learning a foreign language in early childhood, what potential influences there are of foreign language learning on the native language acquisition, and what can be done for the child to benefit from early foreign language learning experiences. With this standpoint, this research aims to analyse the current research studies with regards to the central theoretical perspectives in the literature, and to inform preschool teachers, foreign language teachers, educational policy makers and parents in detail by addressing the concerns, assumptions and considerations for foreign language learning in early childhood. Some of the main findings obtained from the pertinent theories and published research in the literature on the above-mentioned issues are as the following. The two prevailing perspectives for the starting age are the early start view and the late start view, with their own justifications. Native language development may be influenced by learning a foreign language in accordance with native language activation, language practiced and dominance effects, and this backward transfer is usually negative first, and positive with increasing proficiency. More benefits can be achieved in accordance with the teacher’s language proficiency, the child’s length of exposure and parental involvement. The findings obtained from the literature have been discussed and finally summarised with a number of suggestions for teacher training and further research.