At first they tested to see if the numbers might be the vowels but that assumption didn't seem to work out.
Like Umbrian also, but unlike Latin and Oscan, it has degraded all the diphthongs into simple vowels (Volscian se parallel to Oscan svai; Volscian deue, Old Latin and Oscan deivai or deiuoi).
(4) The change of -s- to -r- between vowels as in erom, " esse".
Vocalic harmony is the internal bringing together of vowels of the same class for the sake of greater euphony, while vocalic dissimilation is the deliberate insertion of another class of vowels, in order to prevent the disagreeable monotony arising from too prolonged a vowel harmony.
The consonants are for the most part reproduced pretty distinctly, but not the vowels as yet in an equal degree."