Dia daoibh a chairde, just a quick question.

Should it be sé phointe déag or sé phointe dhéag?

I can't remember if imread somewhere once upon a time that if the noun ends with a vowel it lenites the "déag".

'Maith agaibh

I believe the rule is that déag is lenited if the preceding word is singular and ends in a vowel, or is plural and ends in a slender consonant (except for the word cinn, which is an exception).

_________________
I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.

Lenition of déag when the noun is singular and ends with a vowel, indeed.

Now, I found a few examples of a plural noun that ends with a slender consonant, in Tobar na Gaedhilge, and "déag" isn't lenited : cúig cloigin déag (in "Thiar i dTír Chonaill", by Séamas 'ac Grianna), also "ar chúig pighinn déag" ('Nuair a bhí mé óg", by S. 'ac Grianna), "trí cloiginn déag" (same book).

The grammars don't talk about that rule, nor M. Mechura's PDF about numbers in Irish.

_________________
Is fearr Gaeilg na Gaeltaċta ná Gaeilg ar biṫ eile
Agus is í Gaeilg Ġaoṫ Doḃair is binne

The Mac Congáil grammar does have the rule as I stated it. I also checked FGB (under the word déag), and it states the rule the same way. Of course, that doesn't mean that there are no dialectical variants.

_________________
I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.

Go raibh míle maith agaibh

Dentals rule possibly?

_________________
The dialect I use is Cork Irish.
Ar sgáth a chéile a mhairid na daoine, lag agus láidir, uasal is íseal