Má bhíonn Máirtín ann, bíonn Cáit sásta.
If Máirtín is there, Cáit is (normally) pleased.

Mara bhfuil tusa sásta, ní bheidh mise sásta.
If you are not satisfied, I will not be satisfied.

My question concerns the negative form, mara, which Ó Siadhail translates as "if...not, unless."

I actually have a number of questions but it would probably be most productive if I can first ask, is there any reason why the term "má ní" is avoided in favor of "mara"? Or, is "má ní" acceptable as a more precise statement?

GRMA!

+ > Má = if;
- > Mura (Mara) = if not.

Níl 'má ní' (mhír dhiúltach) ceart in am ar bith a Dhomhnaill.

"má ní" had developed to "muna", "mara" in the past (Old Irish).

Lars

Usually in these sorts of circumstances, it looks like the r is from 'ro'

Looking at the history of a form can help fix it in memory.
For example: from bí (habitual) we can derive do bhí (past) and do bhíod(h) (imperfect). From the root 'be' one can get beid(h) and then do bhead(h).

I read once that the Irish conditional developed from the future, and the imperfect from the preterite. The subjunctives are a little different, but easily derived too. 'Wait till I (will) see' in the present (fan go bhfeice mé) and the past subjunctive is ultimately derived from the past too. Reminds me of HE 'if that fell on you'/'if it came down on you' (if that were to fall upon you)

Maybe this is a psychological thing -I had a student write this, when asked to imagine trading places with his parents: "If I am trade places with my parents, I will go to Las Vegas", where one might expect 'if I were to...I would...'

His example illuminated a few functional aspects I had not considered, so I think looking at the history of parts of the language can be useful