I gathered a few questions while learning Latin (I’m still learning it), and most of them my books could answer, or give tips to where could I find the answers. I can’t find the answers to some of them, though:
1- how do we know that “poena” has the “oe” diphthong and “poeta” does not?
2- one of my books say that I can write “filiabus” for “filiis” (fem. plur. dat. & abl.) and that some nouns use -ubus in the fourth declension to make plur. dat. & abl. (namely: lacus, quercus, portus). Is this considered classical? Has there been a time where the plur. dat. & abl. of the declensions were “-abus, -obus, -ibus, -ubus, -ebus”? Is there any Roman author that explains the cases and declensions, and why were they like this in 1 C.E.?
3- some say the ligatures “ae” and “oe” can be found in Roman papyri. Is this true? Who has written like that? Where can I see it?
4- whatever happened to “uis” (power, force)?
5- whatever happened to future indicative of the 3rd and 4th conjugations?
6- how many vowel lengths are there in Latin? I’ve seen dictionaries that marks every vowel with a macron or a breve (suggesting that there are only 2 vowel lengths) and I’ve seen books that write pure vowels, macron’d vowels and breve’d vowels (suggesting 3 vowel lengths). My guess is there are only 2, but that would mean there is no difference between “rosa” sing. nom. and “rosa” sing. abl.. On the other hand, 3 vowel lengths would seem too artificial to say. Back-up’s from Roman authors are welcome.