On what basis can one claim that nominal plural is inflectional?

[zaba]

Say we have a language that has words like this:

Cat-nom.pl 'cats'
Go-verb.pl-2nd.person-past 'y'all went'

Just note that the plural is optional in these and all examples.

On what basis can I assert that nominal and verbal plural suffixes are inflectional?

I mean, What sort of examples could I show you to make you say, "aha,well, that's obviously part of inflection and is certainly not derivational!"

[Daniel]

The general argument that I have heard is that the plural suffix does not change the meaning in any way. Instead, it is grammatically conditioned when speaking about multiple entities.
Personally I find that explanation a bit confusing, but if you accept it, then it should be easy enough to apply it to other languages.

Consider:
dog
dogs

There's no real meaning difference between those words except in number. There isn't a case where the plural means "cats". In derivational morphology, some things are irregular including in the meaning.


However, in general I don't see the point in distinguishing between "inflectional" and "derivational" because it's actually somewhat fuzzy. If you look at serious research on the subject, it's not a simple dichotomy, or at the very least the available evidence doesn't always provide enough information. The distinction should be used if it helps you to describe the language; but the description should not be used if you are forcing the data into arbitrary boxes because of it.

[lx]

The distinction should be used if it helps you to describe the language; but the description should not be used if you are forcing the data into arbitrary boxes because of it.

Absolutely could not agree more.