Neither system completely differentiates long and short vowels; the Nestorian scheme is the more satisfactory, though more cumbrous.
The text of the Old 'Testament consists of consonants only, for the alphabet of the ancient Hebrews, like that of their Moabite, Aramaean and Phoenician neighbours, contained no vowels; the text of the interpretation consists of vowels and accents only - for vowel signs and accents had been invented by Jewish scholars between the 5th and 9th centuries A.D.; the text of the Old Testament -is complete in itself and intelligible, though ambiguous; but the text of the interpretation read by itself is unintelligible, and only becomes intelligible when read with the consonants (under, over, or in which they are inserted) of the text of the Old Testament.
Miss Keller's vowels are not firm.
In many varieties of the Greek alphabet this symbol was used, as it always was in Latin, for the long as well as the short o-sound and also for the long vowel (in the Ionic alphabet written ov) which arose from contraction of two vowels or the loss of a consonant (57jXoUTE=677XOere, o'lxovs = oircovs).
Robinson, K. & PATTERSON, R.D. APU 3314 The stimulus duration required to identify vowels, their octave, and their pitch chroma.