How to test for nasality

It's relatively simple: the only full-nasal sounds in English are "n," "m," and "ng," so, you can take any vowel, hold it, and then pinch and release your nose (say at 2Hz or so) and then if there's no detectable change in sound, your are oral. Otherwise, if you clearly hear change in sound while pitch/releasing, you are nasal, where you should not be.

Some notes: this test is pretty good, but you can still miss some nasality with it if it's subtle. Also, in speech, vowels can be a bit nasal and that's fine in certain context, for example when they are close to those nasal consonants mentioned (then the vowels will be colored by nasality a bit.) But, if you have a word, like, say, "say," there should be no significant nasality in principle.

Here's a demonstration of this - note that the second vowel is done exactly the same way as to pinching, but it sounds like nothing is happening while the first vowel has drastic fluctuation due to nasality being in place (where the airflow wants to go through the nose.)It's relatively simple: the only full-nasal sounds in English are "n," "m," and "ng," so, you can take any vowel, hold it, and then pinch and release your nose (say at 2Hz or so) and then if there's no detectable change in sound, your are oral. Otherwise, if you clearly hear change in sound while pitch/releasing, you are nasal, where you should not be.