Child Psychology is the science which studies, describes, and explains the behavior and development of mental and cognitive processes and skills, as well as the individual differences among children. According to the age periodization of child development, the ages between two and six are classified as early childhood, which most often include toddlers and preschoolers. A stimulating environment is an important factor in foreign language acquisition for people of all ages, but it is especially the case for children and youth. Sociology, medicine, natural sciences and neurosciences are (in addition to developmental psychology) seeking to identify the factors which contribute to achieving a faster and more efficient development of children's cognitive and social skills along with making foreign language learning simpler and more interesting. Contrary to the previously widely accepted misconception which maintained that cognitive skills are inherited and independent of external factors, they can be developed and improved upon so that all children can achieve their full potential. Early brain stimulation, as well as early stimulation of creativity, imagination and other cognitive abilities, along with the support of the child's family, educators/teachers and peers and an encouraging environment all contribute significantly to a faster and more efficient new knowledge and skill acquisition. For years experts have proposed encouraging the teaching of foreign languages and other skills to children of kindergarten and preschool age because it was proven that, at said age, children can speak fluently up to several languages at the same time. Moreover, practice has shown that traditional language learning methodology is inadequate, so Maria Montessori and Helen Doron methodologies are instead used more often. Learning a foreign language, primarily English, in early childhood is a well-established practice worldwide, as a part of the lifelong education concept. For the past 20 years, efforts have been made in the Republic of Croatia to introduce early language learning educational programmers and methodological approaches to almost all kindergartens. The Maksimir Kindergarten in Zagreb introduced the full-time early-age English learning programmed, approved by the Ministry of Education, Culture and Sports, as early as 1998 and educational institutions, in accordance to the instructions that the Ministry of Science, Education and Sports of the Republic of Croatia provided, with the aim of making learning English as a foreign language an integral part of the lifelong learning and education system.