As A&G note, “The i-stem was confused by even the Romans themselves.” There are a variety of variations with this stem present in all three grammatical genders, making it incredibly difficult to organize the data except in broad patterns and rote memorization. To that effective, I’m going to design a series of posts on the i-stem declension.
In this section, we’ll introduce the i-stem as a morphological class, and discuss the declension of ‘regular’ masculine and feminine i-stem nouns.
First off, all i-stems are either pure or mixed.
Most pure i-stems are immediately identifiable by their lexical entry, because they feature parisyllabic (having the same number of syllables) nominative and genitive forms. This is true of masculine, feminine and neuter i-stem nouns. However, most masculine and feminine nouns also have nominative and genitive forms that are completely identical. Let’s take a look:
sitis, sitis (f.) thirst (declined only in the singular, for sensible reasons)
ignis, ignis (m.) fire
A few unique features to note:
- nominative singular -is (except in four cases, see below)
- accusative singular –im (though not always)
- ablative singular -ī (though not always)
- genitive plural -ium (strictly)
As you can see, there aren’t many markers (just one) that guarantee any given noun is an i-stem noun. In fact, it would be possible to decline ignis in a way such that only it’s nominative singular and genitive plural gave any hint of the i-stem status.
With four nouns in particular (imber, rain; linter, skiff; ūter, wineskin; venter, belly) this problem is even more evidence because here even the nominative is lost as a distinctive feature. The only morphological form that demonstrates imber‘s i-stem status is its genitive plural imbrium.
So to review masculine and feminine i-stem declension: difficult, difficult, difficult. As we’ll see, the neuter declension isn’t much easier…
The essential AG: 66-7.