Reading Califf’s Latin Meter and Verse Composition and surprised by the talk of ‘lengthened vowels’: surely it is the syllable and not the vowel that is long in virtue of the vowel’s position? Is this merely impræcicely expressed or am I missing something?
Quotation of the passage in question would help, but it does sound as if he may be conflating lengthening of syllables with lengthening of vowels. Does he talk of lengthened vowels throughout or does he sometimes refer to lengthened syllables as well? If the latter, then it’s likely he’s assuming that when he says lengthened vowel you understand him to mean lengthened syllable.