FWIW, I just downloaded this app and tried out their diagnostic test. It gave me a rating of 94% and (correctly) classified me as a native speaker. So that’s some evidence that at least the test does not have a high false negative rate.
FWIW, I just downloaded this app and tried out their diagnostic test. It gave me a rating of 94% and (correctly) classified me as a native speaker. So that’s some evidence that at least the test does not have a high false negative rate.