Classroom principlesSome of the basic principles of CLIL are that in the CLIL classroom:Language is used to learn as well as to communicateIt is the subject matter which determines the language needed to learn.A CLIL lesson is therefore not a language lesson neither is it a subject lesson transmitted in a foreign language. According to the 4Cs curriculum (Coyle 1999), a successful CLIL lesson should combine elements of the following:Content - Progression in knowledge, skills and understanding related to specific elements of a defined curriculumCommunication - Using language to learn whilst learning to use languageCognition - Developing thinking skills which link concept formation (abstract and concrete), understanding and languageCulture - Exposure to alternative perspectives and shared understandings, which deepen awareness of otherness and self.In a CLIL lesson, all four language skills should be combined. The skills are seen thus:Listening is a normal input activity, vital for language learningReading, using meaningful material, is the major source of inputSpeaking focuses on fluency. Accuracy is seen as subordinateWriting is a series of lexical activities through which grammar is recycled.For teachers from an ELT background, CLIL lessons exhibit the following characteristics:Integrate language and skills, and receptive and productive skillsLessons are often based on reading or listening texts / passagesThe language focus in a lesson does not consider structural gradingLanguage is functional and dictated by the context of the subjectLanguage is approached lexically rather than grammaticallyLearner styles are taken into account in task types.