Long and short vowels

Latin Learning Latin
1

Are these rules final when it comes to when a vowel will be short or long. I’m only referring to verbs here, in which I found this pattern. I couldn’t find anything in Gildersleeve or A&G. Could anyone refer me to these rules in either, or why not both grammars if possible, i.e. if they are even definite rules and if they are even found in both grammars.

Gratias vobis ago.

A vowel is short before final: -m, -t, -r

A vowel is long before final: -s

A vowel is long before the following when within a word: -m-, -r-, -t-

Final -i is always long.

A vowel is always short before the following regardless of whether it’s within a word or at the end of a word: -n-/-n, -nt-/-nt

2

I’m afraid some of those “rules” are not correct. Just a few examples:

In words like legis (< legere, legō), capis (< capere, capiō), the i before the final s is short, not long.

Vowels are not always long before -t-, e.g. in the words iterāre and percutere,

Vowels are definitely not always short before -n-, e.g. in the verbs pōnere, fīnīre, and dōnāre.

I think your approach to vowel length is a bit simplistic. While there are some patterns, vowel quantities really have to be learned by memorising, listening to experienced speakers and reading poetry, among other things.