Short and long vowels. How to know?

[Andrus]

Salvete.

After I had finally solved my problems with the sounds of the Latin’s Alphabet (once more my thanks Luigi_Pirex) here I am again with a new problem.

How can we tell if a vowel is short or long only by the rules given in #12 of the book (page 18 of pdf).

I’m guessing (D’Ooge doesn’t mention nothing about) that in words that end with a vowel, this last vowel can be short or long depending on the grammatical function (like the last “A” in aqua that is short for the Nominative case and long for the Ablative case).

I also know that for the verbs in the consonant conjugation in the infinitive the last “E” before “-RE” is short while for the verbs of the second conjugation it is long. So here we have to know before in what conjugation the verb it is.

But in the other situations how can we know the quantity of the vowel if it isn’t marked?

Given some examples from words of exercise #10 of the same page (I will mark long vowels with bold type):

1 – disce

Both vowels are short. Considering only the “I”, were there anyway to know that vowel is short?
Because the “I” don’t go with any of the rules given, how could we know?
If there aren’t anyway to tell, is there any propose in memorizing the #12 rules?

2- sapientiam

Here all vowels are short once more. There are reasons for all vowels except the first “A”. Once more is it possible to know that without had seen the word before with that indication?

In other subject, but related, how can I know if the combination of 2 vowels are a diphthong or not?

Thanks in advance for any help.

Andrus.

[benissimus]

Salve Andre,
The rules concerning vowel length in that section of the book merely show some reliable rules. In most cases, you will simply have to know the word if you wish to know the vowel lengths. If you had to guess the length of a particular vowel, then these rules would help. There are indeed some words containing vowels of which no one knows the length for certain.

In other subject, but related, how can I know if the combination of 2 vowels are a diphthong or not?

If two vowels that can form a diphthong together are adjacent to each other, then they will form a diphthong. The diphthongs are ae (rarely ai), oe (rarely oi), ei, eu, ui, and au. The exceptions is that if one vowel is short and the other long, as in poeta, then the diphthong does not form (in poeta the O and E are pronounced separately for example). If there is a diaeresis (¨) over a vowel, then it is to be pronounced separately of course (e.g. Laocoön, not that two O's could form a diphthong anyways).

[Andrus]

Salve Benissimus,

So by your explanation it is best to assume that they form a diphthong unless we know from the start that they aren’t.

In this subject I think that the fact that I’m Portuguese will help as I would never thought the “oe” in poeta would be a diphthong. Because in Portuguese the word is spoken as po-e-ta, like in Latin.

Once more thanks.

Andrus