English as a Second Language (ESL): IELTS
About the IELTS
"IELTS is the International English Language Testing System.
Over 6000 organisations and more than 1.5 million test takers around the world recognise the IELTS as an indicator of ability to communicate in English for education, immigration and professional accreditation.
The IELTS is administered through more than 800 test centres and locations in over 130 countries."
--from "IELTS: About", on the IELTS official website.