The text provides an in-depth look at diphthongs, which are complex vowel sounds formed by combining two adjacent vowels within the same syllable. It categorizes diphthongs into several types:
They are the ones that start and end with a closed vowel, like this: iu ui
Decreasing
Are those that end in a closed vowel, like this:
ai ei oi au eu ou
Increasing
They are those that start with a closed vowel (i, u), because when they are pronounced it increases the opening of the vowel from / i / or / u / to the next vowel, like this: ie ia ua ua ue uo
TYPES OF DIPHTHONGS
WIDE DIPHTHONGS
NARROW DIPHTHONGS
They are comprised of vowel sounds and similarly pronounced.