"Grandfather! What is your name?"
Translation:A sheanair! Dè an t-ainm a th' oirbh?
I can see the point of this situation; however, I would like to question unrealistic examples – or are you deliberately using such phrases in the hope that they'll stick in our memories better than "mundane" ones? ;)
Also, and on a slightly more serious note, are there lots of Gaelic speakers who don't know their grandfathers' names?
There was definitely a time in my life when I just knew my grandfathers as "Granda" and "Grandad" and didn't know there first names. I don't think that's uncommon for young kids. And, yes, Granda is a common way of addressing your grandfather in Scotland, despite the Gaelic word "grànda", which I didn't know before this course :-)
Hey! So you're absolutely right in that oirbh is used as the plural form of ort, but it is also used as the formal or polite form. So you would use oirbh with parents, grandparents, teachers, officials, clergymen, etc. Pretty much anyone of higher rank or status than you, or just someone you don't know well and so want to be extra polite to :)