Cognitive Development and Optimal Age to Start Second Language Learning with an Emphasis on English as a Foreign Language

The present research aimed to achieve the appropriate age range for starting language learning by synthesizing the research conducted between 1961 and 2023, considering the factor of cognitive development. The present study followed a synthetic research approach. After two rounds of screening, 39 studies between 1961 and 2023 entered the analysis step and the data were analyzed. The data were combined according to the purpose of the coding. The Guba and Lincoln’s indexes which include credibility, transferability, and dependabilty were used to validate the data. 51 open codes, 9 axial codes, and 3 selective codes were obtained. The selection codes were "the optimal age to start foreign language learning", "relationship between age and accent ", and "necessary conditions for children's education”.  The majority of researchers agreed on the age range of 6-10 years. The beginning of language learners in the mentioned age range requires requirements to significantly change the success rate of language learning in formal education. The results help the policymakers to achieve the goals of the National Curriculum.