Does Duolingo publish an official list of speaking topics?

When you apply for admission in any university with your DET score, the admission committee needs no verification. As Duolingo itself share the scorecard of your test directly to the university through its secure portal. This is to ensure authenticity and prevent tampering.

Yes, you can send your certified Duolingo English Test score report to as many universities as you wish. It is free of charge.

If you have not started your Duolingo English Test only then you can request for fee refund. Log in to your DET account and raise the refund request withtin 21 days of purchaging the test. Remember, after the DET test is started or the 21 days window passes, you can not ask for refund.

No, Aalto University Finland does not accept Duolingo test for admission to Master's and Doctoral courses where the language of instruction of the course is English. But, to prove the English language proficiency, international applicants are required to submit the minimum scores given below: 

Yes, Duolingo offers official practice questions on it's official website. Also, you can find other free resources it's YouTube channels. Also, you can commuincate with other test takers on plateforms like reddit and quora. This will help you to have an idea of new pattern.