Assertion: diphthong's vowel | /r/HasProperty | open
Facets:
value: sometimes
type: TEMPORAL
Source sentences:
text: So first of all, you should recognize if the vowels are open or closed.
text: The strong vowels of Spanish — sometimes known as open vowels—are a, e, and o.
text: Spanish diphthongs are formed by one open vowel (a, e, o) +