Third Declension Consonant Stems

Latin Learning Latin
1

HONOR is declined from dropping the genitive -IS and so is PATER, but PATER is changed for minor pronounciation reasons.

HONOR PATER
HONORIS PATRIS
HONOREM PATREM
HONORI PATRI
HONORE PATRE

The following words are declined from the Consonant Stem: DUX, REGIS, MILES, PRINCEPS

DUX MILES
DUCIS MILETIS
DUCEM MILITEM
DUCI MILITI
DECE MILITE

HONOR and PATER are declined by dropping the -IS of the genitive while DUX, REGIS are delined from the consontant stem? An example
of DUX being formed is:

DUX placed in Noun Base DUCORUM minus -ORUM gets you DUC. DUC and an -S form DUX. For some reason DUX is different than HONOR. HONOR is straight out declined from the genitive without any explanation about noun bases. DUX needs explanation because declining it changes the spelling. Is this correct?

If this is so what explains the following:

FLUMEN CORPUS
FLUMENIS CORPORIS
FLUMEN CORPOR
FLUMENI CORPORI
FLUMENE CORPORE

These are neuters which do not add ‘s’ but behave like DUX and there is some trick to declining them, needing you to observe the consonant stem. They are aparently behaving diifferntly in declining than HONOR or at least the book is calling attention to them. FLUMEN with the genitive FLUMENIS doesn’t seem to change its spelling but CORPUS with the genitive CORPORIS does. What is the trick to declining these? The book is calling attention to DUX, and REX in one group and FLUMEN and CORPUS in another as behaving differently than HONOR when being declined. DUX makes sense (DUX changed to noun base DECORUM which drops the -ORUM and becomes DUC which adds an ‘s’ which turns into DUX), but the book doesn’t say anything about FLUMEN and CORPUS except that they are in there own class. What is the back story in their derivation?

Thanks.

2

I think you are making the third declension much more complicated than it needs to be. For every third declension noun, just memorize the nominative and genitive as a pair. Take the genitive, drop the -is ending, and add to this stem the universal set of third declension endings, and there you go.

The 3rd declension nouns can be divided up into various groups based on how different the nominative is from the stem which is used to form the rest of the cases; however, with one exception (the so-called ‘i stems’), it doesn’t matter which of these groups your noun falls into. In every case, the genitive singular will contain the stem that is used for all the rest of the cases.

You should note that in several cases, the examples you have put up are incorrect:

-the genitive singular of ‘miles’ is ‘militis’, not ‘miletis’
-the ablative singular of ‘dux’ is ‘duce’
-the genitive singular of ‘flumen’ is ‘fluminis’, and so all of the other forms use ‘flumin-’ as their base - with the following exception:
-all neuters in Latin have the same forms in the nominative and accusative. Whatever the nominative form is, the accusative uses that same form (e.g. flumen, corpus).