Paróiste an Daingin's native speakers are really the older people from Lios Póil. The actual native speakers from An Daingean would have disappeared around 1870, according to Tomás Ó Criomhthain. (Of course I am not counting the native speakers from west of Dingle who now live in the town).
Jay Bee wrote:
What would the average age be of good speakers in most of them? 50, 60, 70?
Depends on the area again. Dún Chaoin has very good speakers from age zero up. It's also hard to say what a good speaker is to be honest. For example my grandfather had hundreds of words for plants and animals in our local area (in English), but I wouldn't have a fraction of this particular vocabulary, does this make me a "poor speaker of English". I think there can sometimes be a conflation between the natural loss of vocabulary related to rural objects/events that has happened in several languages and the actual decline in the language when it comes to Irish.
However there is a tendency in my experience for younger speakers to not really have grammatical gender in their Irish and for lenition and eclipses to be quite hit or miss, a good few wouldn't have the blas as Bríd said. However there are "mistakes" in the Irish of people up to sixty years old. In Munster what I have heard is that those in the 40s-50s might not have the traditional genders that nouns had in the dialect, as well as slightly off stress on words and dialectal mispronunciations. Is this just being pedantic, I don't know. (They don't always have the Caighdeán gender either, sometimes the Caighdeán gender and the dialectal one are the same and they have a different one).
An interesting one is that I had noticed people don't tend to make use of the habitual past much in speech, instead of saying:
Théinn ar an mBuailtín = I used to go up to BallyFerriter.
They say:
Chuas ar an mBuailtín go minic = I went up to BallyFerriter often.
Apparently good speakers have used the former for one hundred years and other speakers have used the latter. Good speakers (even those in their 20s/30s) use the former today. So the distinction here isn't age related.
Hard to know!
