Hi! I think I have everything straight so far on indirect relative clauses, but I want to be 100% sure; so I thought I’d give a couple of examples that I think are correct, and see if anyone can confirm?

That’s the man: Sin é an fear. I read about him: Léigh mé faoi.

Combined sentence: Sin é an fear ar léigh mé faoi.
(That is the man that I read about.)
The past-tense indirect relative particle “ar” was used, and it would have lenited the following verb, had the verb been lenitible.

- - - - - -

I’m going to a new restaurant: Tá mé ag dul go bialann nua. I read about it: Léigh mé fúithi.

Combined sentence: Tá mé ag dul go bialann nua ar léigh mé fúithi.
(I’m going to a new restaurant that I read about.)
Again the particle “ar” was used for the same reason. And, this time, “fúithi” was used instead of “faoi” because it refers back to the feminine noun “bialann.”

Thank you to anyone who can confirm!

I can.

An old fashioned way would be (for both):

... faoinar léigh mé.

Go raibh milliúin maith agat, a Labhrás!

What is the history of this "faoi" (=under) used to mean "about"? Has it always been like that in the North and West? [By the way, the most historical form of the preposition is fa, from which fá fé fí and faoi derive] As far as I'm concerned it is "ar" that should be used here.

sin é fear gur léas air (it feels a bit bare; what about sin é fear gur léas mar gheall air?)
sin é fear ar ar léas (sa nuachtán, i leabhraibh)

afaik: um -> má -> fá -> faoi

OK, I didn't know it was from "um".

Yes, in Classical Gaelic the two merged to some degree. The poets used fa, fo, fá (3rd sg. fáoi) + dative in the meaning ‘under’ and um, im, ma, bha, fa + accusative in the meaning ‘about, around’. The latter had a lot of variation and seems to mostly have merged with fa, fo in Ireland (but rather kept distinct in Scotland, there still fo ‘under’ vs mu ‘about, around’).

I had assumed from Labhrás' post that these had the same etymological origin, both m and f being labials. Do you mean they were originally distinct and then merged?

Also: um is not used that much, but Peadar Ua Laoghaire stated he could not live without it. casóg a chur umat (not "ort") was his form.

But what about faoi meaning "about (not in the sense of "around", but in the sense of talking about something)? Has that always been found in Irish? Those websites that have a page entitled "fúinn" are painful (to me), appearing to mean "under us", which I would expect as "mar gheall orainn".

Yes, they were distinct and (not fully) merged during Middle Ages. Originally (ie. in Old Irish) there were two prepositions:

• fo took dative (in the static sense; acc. when motion was involved) and meant ‘under’ (this comes from PIE *(s)upo → Celtic *u(ɸ)o → Prim.Ir. *wo → OIr. fo, cf. Latin sub, Greek ῠ̔πό, and also on the same root super, over): https://dil.ie/22333
• imb, imm took accusative and meant ‘around, about’; used in the geographical and temporal sense, and also in the ‘concerning something, talking about’ sense (PIE *h₂m̥bʰi, cf. Greek ἀμφί, Latin ambi-): https://dil.ie/27635

By Classical Gaelic (ie. during Middle Irish) the latter had developed multiple variant forms like um, ma, bha, fa (besides directly inherited im) and was conflated with fo, fa to some extent – contaminating fa, fo itself and giving it the meaning ‘around, about’. So that meaning for fa, fo (later faoi) exists in Ireland at least since late 12th century, but originally it came from the other preposition and originally was distinguished from ‘under’ by the grammatical case used (dat. vs acc.); and also forms im, um, ma, bha were used exclusively in the meaning ‘around, about’ (never as under, beneath).

Nice post silmeth

The only time I've heard "um" is "im Cháisc" and "im na Nollag". Nollaig taking the genitive with prepositions is a Paróiste Múrach feature.

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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