Assertion: vowel's sound | /r/CapableOf | sound within same syllable
Facets:
Source sentences:
text: A diphthong ( DIF-thong or DIP-thong; from Greek: δίφθογγος, diphthongos, literally "double sound" or "double tone"; from δΐς "¨twice" and φθόγγος "sound"), also known as a gliding vowel, is a combination of two adjacent vowel sounds within the same syllable.