Schools throughout the world teach in several languages, but few reach the level of linguistic proficiency of Hamelin-Laie International School in Mongat, Barcelona, Spain. This school begins instruction in English, Catalan, and Spanish and at grade one, adds a fourth language as a World Language. Factors that impact the success of this school were studied, including: The commitment to language learning is evident in all aspects of the curriculum. Teachers highly proficient in the language and culture of instruction provide constant attention to the development of oracy and literacy in all languages. External international examinations reflect high expectations for language proficiency. The student body encompasses infants to baccalaureate level. A very well developed review process enables educators to continually refine and expand the effectiveness of the program to create a developmental progression of social, emotional, linguistic and academic growth from birth to university that is truly remarkable. All of these factors encapsulated within an interactive, hands-on, meaningful curriculum that fosters development of higher order/global thinking are the hallmarks of the Hamelin-Laie International School. The success of the program is owing to many factors, the greatest of which is that the students are not learning languages but using languages to learn.