"There is no thunder."
Translation:Chan eil tàirneanaich ann.
Mark says that the word is tàrneanach except in Lewis where it is an tàirneanaich, but then goes on to give examples with tàirneanaich.
Now tàirneanaich is simply the plural of tàirneanach, so it looks as if tàirneanach is usually treated as the singulative 'thunderbolt' and so the plural is used for a thunderstorm consisting of lots of bolts. I think his comment about Lewis is simply that it is treated as singular there (which you cannot actually tell in any of the sentences we have had so far).
tàirneanach, -aich nm thunder (used in the form an tàirneanaich in Lewis) thunder □ bha tàirneanaich is dealanaich ann anraoir there was thunder and lightning last night □ is gann gun cluinneadh tu mothar an tàirneanaich you could scarcely hear the roar of the thunder
We have to be very careful with the last example, as here an tàirneanaich could be genitive singular of an tàirneanach or (presumably) an tàirneanaich, but not the genitive plural. D