Since 1964，colleges and universities in the U. S. have used Test of English as a Foreign Language，or TOEFL，to measure an international applicant's（申请人的）level of English. Universities in English-speaking European countries began using the International English Language Testing System，or IELTS，in 1989. These two tests have been the main choices for English ability testing in higher education admissions for international students until now.

In recent years，several companies have developed new English language tests that are low-cost and easy to use. And they aim to do more than just offer greater choices in the admissions process.

Founded in 2012, Duolingo creates software that teaches users many different languages, including English. In 2014, the company launched its own test of English language ability.

Jennifer Dewar works with Duolingo, helping to develop the test. She formerly worked as an admissions official at Washington University in St. Louis, Misouri. The school is one of hundreds of colleges, universities and other organizations in and outside the U. S. that now accept the test results for international admissions into their study programs.

Dewar says Duolingo created the test to lower the barriers to higher education for people worldwide, especially those in developing countries.

TOEFL and the IELTS cost about $ 300. They are given in a limited number of centers around the world. Some test-takers have to travel to take the tests, adding to the costs. Duolingo offers its test entirely over the Internet for $ 49. All test-takers need is access to a computer with a microphone，listening device and self-facing camera.

TOEFL，the IELTS and Duolingo measure a person's English reading，listening，speaking and writing abilities. But it takes about 45 minutes to complete a Duolingo test，compared to three or four hours for TOEFL or the IELTS. It is possible because Duolingo uses artificial intelligence（人工智能）to adapt to test-takers' abilities，using fewer questions to measure their skills.