IELTS, International English Language Testing System, is an international individual certification on a candidate’s level of knowledge of the English language. This certification has very high standards and international recognition, therefore this test is the most sought-after in the world. It was developed by the IDP IELTS Australia and University of Cambridge ESOL. IELTS complies with the highest international linguistic assessment standards, which covers the four main language skills: listening, reading, writing and oral communication. This certification is usually needed to work abroad.