Latin vowels look like English vowels but generally have different pronunciation. Each vowel carries only two sounds, one long and one short. All ablative singular forms of the second and third and fourth declensions are thus long. Dative singular forms of the second and third declensions are also long. We 'know' also that the ablative singular of the first and fifth declension are also long.
Stress is placed on the penult if it is long and on the antepenult if the penult is short.
The 'a' of a 1st conjugation verb is long. The 'e' of a 2nd conjugation verb is long. The 'i' of a 4th conjugation verb is long. Scholars have used lines of poetry to determine sounds of Latin words. A 16th century physician named Smets organized a dictionary based on their findings.