Can anyone tell me what the difference is between (if any)
Tá a fhios agam and Is fios dom ?

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Bíonn rudaí maithe mall

Well there is a subtle difference between Is eol dom and Tá a fhios agam,
but I've never heard or read Is fios dom in native speech or writings before, where
did you find it?

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

Tá a fhios agam / Is fios dhom / Is fios liom. An rud céadna dá ríribh, ach tá's 'am amháin I gConamara.

I hadn't heard it myself, i came across it in the Cork Irish dictionary , page 372, under Fios.

Seaghan are you saying Is fios liom is a Connemara version ?

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Bíonn rudaí maithe mall

Oh!, in that case I read it and forgot it, since I've read Mo Sgéal Féin! Stupid me!

From doing a bit of reading, it seems that Is fios dom was the original version of the phrase, which used the copula. There
are a few phrases like this that switched over from being used with Is to being used with Tá.

EDIT: I should say that since I've never heard this phrase spoken, I'm not aware of any distinction between them. Although
it is likely they mean the same thing, seeing as how they are just Tá/Is variants, as often occurs in the language.

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

Níl.

Personally I'd say -

Tá's 'am (Tá a fhios agam) - I know

Go bhfios dhom/dom - As far as I know.

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It is recommended that you always wait for three to agree on a translation.
I speak Connemara Irish, and my input will often reflect that.
I will do an mp3 file on request for short translations.
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I always thought it was

Tá's agam. or something along those lines.

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Bíonn rudaí maithe mall

The 'g' in 'agam' tends to be pronounced in Munster not in Conamara. The Ulster folk probably do something whacky!

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