So last night I was working with a student, and I realized that we teach inflectional morphology but not derivational morphology.
In fact, the bulk of Latin instruction is inflectional morphology. It's the guts of the grammar for Latin. Sure there's stuff like making sure that adjectives agree with their antecedents, but even that's just inflectional morphology. More to the point, inflectional morphology is regular and has grammatical effect.
Derivational morphology is another story. You'd have to be a dull student of Latin to not catch the similarity between these two:
Anyway, the potential non-productivity of derivational morphemes is a frustrating feature of language.
In fact, the bulk of Latin instruction is inflectional morphology. It's the guts of the grammar for Latin. Sure there's stuff like making sure that adjectives agree with their antecedents, but even that's just inflectional morphology. More to the point, inflectional morphology is regular and has grammatical effect.
Derivational morphology is another story. You'd have to be a dull student of Latin to not catch the similarity between these two:
cīvitās, cīvitātis – citizenshipBut there's something fishy here. The -tās ending is obvious. It forms an abstract noun. But look at the roots.
auctōritās, auctōritātis – authority
pietās, pietātis – sense of duty
cīvis, is – citizenCīvis is a noun. Auctor is a noun. So far so good. Pius is an adjective. How are we supposed to teach that? What's worse is that it's not freely productive.
auctor, ōris – a do-er (more literally, an increaser)
pius, a, um – dutiful
*imperātōritās – ain't no such thingEven though someone who knows Latin can analyze that word. So you can't even predict that it will work at all times. About the only thing we can say about the -tās ending is that it is the abstract noun that deals with the attached root.
Anyway, the potential non-productivity of derivational morphemes is a frustrating feature of language.