Assertion: diphthong's vowel | /r/HasProperty | fronted
Facets:
Source sentences:
text: Vowels were fronted when following a palatal or "soft" consonant (*j, any iotated consonant, or a consonant that had been affected by the progressive palatalization).
text: Vowels within a word "harmonize" to be either all front or all back.
text: Latin cuculus) suggest an archaic [uː] pronunciation of long upsilon, before this vowel was fronted to [yː].