What sort of morpheme is this suffix meaning ‘about'?

Question

Some background: This is a conlang that I'm developing as part of my job. It's a difficult task, but I want to make it as realistic as possible. I have to make a detailed grammar so that other linguists can write dialog for characters. Obviously, I can't foresee everything, so I'd like to base the details of this language in existing ones.

This is a highly agglutinative language with derivational and inflectional suffixes, perhaps like Quechua. It has case. There are no prepositions.

The word 'about' should be a suffix too, but I don't see any reference for such a suffix in the literature. Here are some sentences I'd like to be able to gloss in the grammar:

3SG.PRES-be joke dog-about
`it is a joke about dogs’

1SG.FUT-tell you-DAT tooth-about
‘I will tell you about a tooth.’

I know you can’t just tell me how to categorise this suffix, but any input would be helpful. For one thing, I’m not sure if it’s best classified as inflectional or derivational. Also, I cannot really think of a good gloss.

Answer 1

The morpheme would probably be best described as a case suffix. In natural languages the oblique case often has the meaning of concerning/regarding, but it also has other meanings. If you wanted a label purely for this meaning I think you'll need to make one up. One option would be regardive.

I'd wonder though if you're really being tied too much to the English. Notice that in your first example the case marks a relation between two nouns, but in the second it marks a relation with the verb. Languages with productive case will have verbs which require their arguments to be in particular cases, just as many English verbs require their arguments to be prepositional phrases. Would it be possible to say "1SG.FUT-tell you-DAT tooth"? Without that contrast the case marker is actually almost semantically empty. That doesn't mean you shouldn't do it, because many languages do, but it just seems to me that the only reason the suffix is there is because the English translation would use the word 'about', not because it necessarily makes language-internal sense.

The English word tell is really polysemous and has two meanings: tell to and tell about/of. That's why it almost always requires one of those prepositions. In your constructed language there's no reason why tell should also have those two meanings - it would probably be more natural to have two verbs. If you did that then you wouldn't need the suffix. And if you did that then you could reconsider what the suffix actually means: does it mean a joke with dogs in it? If so then one of the spatial cases would be very appropriate. Just as in natural languages, physical relations can be extended to metaphorical relations in conlangs too.

Instead of basing it on English prepositions I'd encourage you to think about basing it on thematic relations. Your conlang will be less Englishy if your cases are based on those relations rather than translations from English.

Answer 2

There are some constructed languages with such a case. In Ithkuil (a constructed language with an excessively large case system) the case is called Referential case.

It is also conjectured that such a case exists in Tolkien's language Quenya, and several names are suggested for it including Respective, Dedative, and Relative case.

Answer 3

In Riffian, "about" is translated by a morpheme that was originally the preposition "on/over". Then, your oblique case can derive from such a preposition. Natural languages are conditioned by the principle of linguistic economy, so they only do the necessary. It is more economical to reuse one than to create a new morpheme.