I believe there are no exceptions to this rule. That's what I have always read, and I have never encountered any, neither in Greek nor in Latin, nor even in German.
There is an hypothesis about the cause of this phenomenon. Neuter words were historically limited to inanimate objects or things that cannot act. In a basic sentence, it was rarely or never the ...
(This answer is based on Weiss's Historical and Comparative Grammar of Latin and Clackson and Horrocks's Blackwell History of the Latin Language.)
The first thing to know about these two ablative endings, -e and -ī, is that neither of them is descended from the Proto-Indo-European (PIE) ablative ending.
-e comes most probably from the PIE locative ending, *...
The second form is the genitive singular.
The above answers address the substance of your question, but I wanted to add as a supplementary answer something that doesn't appear to be explicitly stated elsewhere: The genitive singular is the only form that is unique and uniform for each declension.
Unique: No other declension has the same genitive singular ...
First, Galilaee sounds right.
See this question about the vocative of Gnaeus for details.
There are situations where one finds -ee- in Latin without the first e belonging to ae.
What I found is not word-final, but I assume that is not important for your question.
There are forms of deesse and deerrare, and if the diphthong ae is included, also forms of ...
It's the singular genitive-case form. The use is that if you know the nominative singular form, genitive singular form, and the gender of a regularly inflected Latin noun, you can predict all of its other forms. These are the "principal parts" of a regular Latin noun. (Some nouns have irregularities in their inflection that require more description, like the ...
'Why' isn't usually a good question for these types of things, because the answer is often "just because." The Greek isn't typical, but it does have a parallel with o-contracted words like νοῦς, περίπλους, or (neuter) κανοῦν.
Nominative Ἰησοῦς νοῦς
Genitive Ἰησοῦ νοῦ
Dative Ἰησοῖ/Ἰησοῦ νῷ
Accusative Ἰησοῦν νοῦν
You're absolutely right that PIE *a gives Old Latin /a/. But somewhere between Old Latin and Classical Latin, vowel reduction happened.
Basically, Old Latin stress was always on the first syllable. So short vowels in other (non-stressed) syllables tended to get reduced, sort of like how English keeps the i in "combine" but reduces it in "combination".
If you're asking how the third conjugation historically came to use the vowels i/u, it has to do with regular sound changes that affected the original Proto-Indo-European (PIE) endings.
The present indicative active paradigm for this verb in PIE, with its descendant paradigm in Latin, would look something like this:
1sg. *h₂eǵ-ō > agō
2sg. *h₂eǵ-e-si > ...
To answer your second question, this rule is completely exceptionless, not only in Latin but in all Indo-European languages (that is, those that have a neuter gender at all).
neuter gender always had identical nominative, accusative and vocative forms in all three numbers
Archaic Syntax in Indo-European
In a couple of letters where he describes villas (esp. 2.17 and 5.6), Pliny the Younger uses cryptoporticus (Greek κρυπτός + Latin porticus) to describe a colonnade with wall and windows – a covered gallery. Commentators (e.g., A. N. Sherwin-White, The letters of Pliny: a historical and social commentary ad II.17.16) seem to agree that he coined this term.
Secundus is regular, eqvus isn't
There's a sound change called the "Boukólos Rule", which started back in Proto-Indo-European. When labiovelar consonants (like /kʷ/ and /gʷ/) appeared next to /w/ or /u/, they dissimilated and lost their labialization, becoming /k/ and /g/. The rule is named after one of the first known examples, Greek βουκόλος "cowherd".
The Vulgata is full with proper nouns having double -ee, specially as endings (e.g. Bersabee, Phacee, Osee). I imagine you are not particularly interested in these. Below are all the other words I could find:
deest, deerunt, deessent, deerit, deerant, etc. E.g.
Nm 21:5 locutusque contra Deum et Moysen, ait : Cur eduxisti nos de Ægypto, ut moreremur in ...
Since you’re asking about reduplicated perfect (and not reduplicated present, as in bibo < *pi-ph3-e or sero < si-sh1-e, Weiss 2009: 405), I will try to address perfect formation only.
One of the problems is that synchronically we may not see all cases of reduplicated perfect in Classical Latin. However, by drawing on data from Old Latin and other ...
I get zero results for the locative Lesbi in the HP corpus (the results appear to be all genitives), but I find a handful of in Lesbo.
The same applies to a locative Euboeae, in favour of in Euboea.
The locative Rhodi, on the other hand, is common, commoner than in Rhodo, which seems to be limited to Plinius.
Rhodus did contain several major settlements ...
Tuomo Pekkanen's Ars Grammatica (a Latin grammar in Finnish) says that the second declension has three neuters ending in -us: vīrus, vulgus and pelagus.
They are only used in the singular, and accusative is exactly like the nominative (not -um).
I have no clue about the origin of these words.
I'm not sure if these words even have a similar history.
The first form, e.g., cena, is the lemma or lexical form. This is the form you use when looking up words in a dictionary or lexicon.
The second form is the lemma declined in the genitive case, singular number. In this instance, it is cenae.
Robert J. Henle wrote,1
All Latin nouns are divided into five main groups called declensions, and in these groups ...
The story, as often, has to do with Proto-Indo-European laryngeals. Both these verbs had a laryngeal as the last consonant of the root: *deh₃-, *steh₂-. All the forms in Latin are based on the zero grade of these roots (i.e. the form without a vowel): *dh₃-, *sth₂-. Now, when a PIE laryngeal found itself between two consonants, in Latin the result was the ...
It is generally believed is that
"The Italic "1st declension" continues PIE feminine formations ("ā-stems") built with an invariable suffix *-eh2(-)" (Vine 2017: 755)
cf. Beekes 2011 proposal of an ablauting suffix *eh2(-) ~ *-h2(-)).
Weiss notes that
"Masculine nouns of the first declension that we find in Latin are largely personalizations of ...
Playing with a corpus search tool brought up no examples of -quene or -neque in the intended sense.
If chaining was admissible, I would expect to see attestations with -que and -ne, the most common enclitics.
Therefore I would argue that chaining of enclitics is not good classical Latin, but it is readily understandable in modern use.
If the word for "day" had developed perfectly regularly, we'd actually expect to see it in the fourth declension, as it comes from a PIE u-stem! A few traces of this hypothetical fourth-declension are attested, such as the locative diū (which survives Classically in diū "all day") and the nominative dius (which survives Classically in nunc dius > nūdius "it ...
Acc. pl. pelagē occurs in Lucretius, De Rerum Natura 6.619:
at pelage multa et late substrata videmus
This is simply the Greek plural: the word is a loan of Greek πέλαγος, whose nom./acc. pl. is πελάγη.
A Packard search finds no results for vira, virora, vulga, vulgora.
Remember than infinitives are “typically frozen case-forms” of verbal nouns (Fortson 2010: 107; see also Weiss 2009: 445). So, in several IE branches (Balto-Slavic, Indo-Iranian and Italic), there is a “specific infinitive formation often called the supine that is solely used with verbs of motion to indicate purpose” (Fortson 2010: 108).
In Latin, it’s also ...
The supine is, in fact, the remnant of a fourth-declension nominal form, a verbal noun which stood for the action itself. The Plautine comedies still record an intermediate stage of this syntactical use.
For example, we have accusative with ire, as in ire obsonatum "to go shopping" or ire venatum "to go hunting". On the other hand, redire takes the ablative,...
(This answer is based on Weiss's Historical and Comparative Grammar of Latin, which is usually the place to go for this kind of thing.)
The most common Indo-European 3pl active ending is -nt(i), which is part of the familiar set -m(i), -s(i), -t(i), ..., -nt(i). (The 1pl and 2pl are a bit harder to reconstruct because they vary more in the individual ...
To be able to generate a list of candidates, one should know some common ways to produce different principal parts from a given stem.
To produce the present stem (the first principal part as you call it) one might add a nasal before the last consonant.
To produce the perfect stem one might reduplicate the first syllable, with possibility for vowel gradation....
A good question.
Assimilation (voice): * tagto > * takto. This is a common phenomenon,
cf. scribo-scripsi, veho-vixi etc. (see e.g. Weiss, p. 188, I.1);
With dico, there's nothing unusual: diksi, dikto;
With struo: k was inserted there analogically. Verbs ending in a
labiovelar (kw, gw) follow this pattern:
"the labial element of a labiovelar is ...
The form structum seems to have "c" by analogy to stems that had labiovelar consonants in Proto-Indo-European, as Alex B. says.
In frūctus (from fruor) the Indo-European present stem ended in a labio-velar gʷ, but various analogies no doubt account for strūctus, flūxus, old flūctus, uīctum (from struo, fluo, uīuo)
(Vox Latina, W. Sidney Allen, Second ...
Weiss cites, besides alumnus, femina (from a root meaning 'give suck'), calumnia (derived from *kalwo-mno-, from the root of calvor 'deceive'), and possibly also columna and the divine name Vortumnus (if related to verto 'turn', though it may rather be Etruscan). These are not Greek loans but native formations; I don't know when precisely they were formed, ...
Unfortunately, there's no foolproof way to predict a noun stem from the nominative form.
Fortunately, you can predict the stem from the genitive form. So good Latin dictionaries will list both: your examples would be listed as genus, generis and līber, līberī.
The genitive endings are predictable, and also tell you which declension the noun belongs to: ...
This is well-known and virtually all good grammars discuss this (as vowel syncope).
Genetivus singularis helps us reconstruct the original nom.sg. form (synchronically), that's why we learn nouns in Latin in two forms, nominativus singularis and genetivus singularis.
Type A. No change, the vowel was present in all forms.
Nom. sg. pueros > *puers > puer