Neil McLeod wrote:
> Yes, the final word in each line has to be disyllabic. Does the fact
> that conjugated 3rd plural preposition 'doib / diib' is disyllabic
> help us with a date?
Not really. The learned poet were well aware (and probably learnt it
in school) that certain words could be counted as disyllables, when
the metre required it.
> Note that in line (c), 'tooir' must also be disyallbic here (and so
> written as one word). It was later a monosyllable with a long 'ó'. Am
> I right in assuming that the 'o'was short in the disyallbic form?
In all likelihood the length opposition was neutralised in the first
vowels in hiatuses. I am not aware of any way to distinguish between
long and short in that position (but if somebody knows a criterium,
I'd be glad to know). Whether a fada is written on any such vowel
doesn't mean anything.