ILIU too and didn't see 10 examples listed (WIKIPEDIA). Do you think that our speech patterns are so standardized and monotonously the same that people hear and recognize those distinctions in everyday speech? Regular, real people, not linguists or someone making a study?
I tried saying the example words for both diphthongs and monophthongs out loud to see if I could hear two vowel sounds or just one. I am not sure that experiment was very successful. From living so many places during my childhood I have some very regional pronunciations of some words that I have retained as an adult.

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