The International English Language Testing System is commonly known as IELTS. It is a standardized test designed to evaluate the English language proficiency of non-native English speakers who want to study or work in English-speaking countries.  

The four basic language skills of listening, reading, writing, and speaking are all tested on the IELTS test. It is available in two versions: the academic module, which is intended for those who want to study at an English-speaking university or academic institution, and the general training module, which is designed for those who want to work or immigrate to an English-speaking country.