Genitives in -(th)rach

Most Gaelic genitive forms are reasonably close to their nominative forms. One major exceptions is an apparently weird group of nouns which turn an -air into a -thrach ...

Actually they are weird and for a change we won't go into the details of why (something to do with the way the cases system changed between Old Irish and Middle Irish) and simply look at what's going on and how we can spot one of them weirdos.

In modern Gaelic, they only affect feminine nouns for startes. Add to that the second clue that they affect feminine nouns which end in -air and the list of candidates shrinks considerably. That is because by far the most common nouns which end in -air are masculine, where the -air is the agentive suffix i.e. someone who does something: clach > clachair, sgrìobh > sgrìobhadair.

So, let's take a word like iuchair. It's feminine and ends in -air. What happens is that the -ach ending gets stuck on: *iuchair-ach but because that comes out as a three syllable word (which is a bit long from the Gaelic point of view which likes two syllable words) the second syllable (which was unstressed to begin with) collapses to make way for the -ach. And because the ch is broad [x], the slender r [ɾʲ] gets assimilated into a broad [ɾ]. So we end up with iuchrach.

Now the catch (and slightly annoying thing) is that this is a bit weird even for Gaelic so over time the number of words which do that has decreased. Basically people played around a bit and settled on a genitive which wasn't as far off. For example in the case of màthair which used to have its genitive as *màthrach (it still does in Irish). But in modern Gaelic this has changed to màthar. Or the word cuid which used to have the genitive codach ... which no-body really uses anymore. Instead they just use the nominative e.g. meud na cuid seo. Oh, plus that people have also started to switch the gender to masculine to bring them in line with all the other -air words. Machair used to be feminine only but today quite a lot of people treat it as if it was masculine.

So it all gets a bit messy. But here's a list of some common words that still do or used to:

One's that do

acair

acrach

anail

analach

caora

caorach

còir

còrach

dàil

dàlach

dìnnear

dìnnearach

iuchair

iuchrach nathair nathrach peasair peasrach

saothair

saothrach

urchair

urchrach

And one's that don't anymore

cuid (> cuid)

†codach

lasair (> lasair)

†lasrach

muinntir (> muinntire)

†muinntireach

màthair (> màthar)

†màthrach

sàil (> sàile)

†sàlach

suipeir (> suipeire)

†suipeireach

Yu orait long? as they say in Tok Pisin ...