"You had thirteen, friends."
Translation:Bha trì deug agaibh, a chàirdean.
I noticed this confusing puncuation in another part of the lesson. Did the person have thirteen friends? If they had thirteen friends then there should be no comma. Maybe you are trying to convey that there are friends that have thirteen of something. Perhaps...If that is the case. That would be... Friends, you had thirteen (in English). Bit confused as to why that comma is there.
a chàirdean is the vocative case, used to address said friends directly, not to talk about them (in that case you’d need nominative, either càirdean or caraidean, no a in front of it)
This sentence means something like you had thirteen, oh friends! / my friends!, where the part oh friends! is just addressing/calling the friends directly, not saying anything about them. That’s the reason for the comma.
Just like in this very sentence, my fellow learner. :)