(1) Dìreach aona mìos deug roimhe sin…
“Just eleven months before that”. In my annotation guidelines I have blithely stated “Attributive numbers are N/N“, which is fine for aona, but less so for deug, which I am going to treat as N\N. And yet in trì deug mìle it seems fair enough.
(2) Bha Gàidhlig ga bruidhinn air feadh Alba anns an aona linn deug.
(3) Bha sin ann an naoi ceud deug, fichead ‘s a ceithir.
Years and centuries are interesting. In (2), anns an aona … deug means “in the tenth”, as opposed to the other examples where deug means “ten”. In (3) the heads look like ceud, fichead and ceithir, so each of these can be N too.
Different rules apply, however, for the personal numbers: aonar, dithis, triùir and so on because if they are not standing on their own, they are followed by a noun in the genitive, for example dithis chloinne (“two children”) where dithis is N and chloinne is N\N.