"It is a sandwich, is it?"
Translation:Ceapaire atá ann, an ea?
Ah. Ok. So, first, you do have an implied copula. This can easily be written as Is ceapaire atá ann, an ea?, translating as "It is a sandwich that is in it, isn't it?". One was you can identify/classify things is with the Is ____ bí + i + pronoun. In Connacht Irish and Donegal Irish, this is used for emphasis, and is similar to Tá sé ina cheapaire (It is in its sandwich).
However, it is unlikely you will see one come up like this. According to here, it doesn't really fit in with the uses given...Unless it's magically a sandwich somehow.
Why is "Is ceapaire é, an é?" incorrect? Prepositions are battering me.
It wasn't "ea" ; it didn't use "Is..." at all; but I don't remember what it was, exactly (which means I'll probably get it wrong again down the line). But yeah, it probably has to do with sentence structure rules that I don't understand. O_o
I replied below with an explanation. However, according to Gramadach na Gaeilge it's main uses are:
if a recently attained or temporary function, profession or similar is meant.
in tenses where there is no copular form, so, in the future, imperative, as well as in clauses requiring a verbal noun. Most of the time these sentences are logically equivalent to the first point.
So, really, it seems kinda outta place here..