Concept:A diphthong is a single vowel sound that glides from one vowel position to another within the same syllable.
Explanation:The starting and ending sounds of a diphthong are different. For example, the "oy" in "boy" or the "ou" in "cloud" show this glide.
Because the sound moves smoothly between two vowels, diphthongs are called gliding vowels or vowel glides.
Other options are incorrect:
- Pure vowels (monophthongs) have a fixed sound and do not glide.
- Semi-vowels (like w or y) act as consonants.
- Weak vowels (schwa or short i) are unstressed and not gliding.
Thus, the correct term for a diphthong is a vowel glide.
Answer:D. Vowel glides