i wuz cogitating on this point and am relating my ramblings

*in the north we say, 'our kid' and, 'your kid' when referring to siblings but never, 'my kid'

*we also say, our mam and, our dad, but never, 'our mum'-- unless talking about, 'our mum', to a third party in the presence of a sibling

*in the tv adaptation of Pride and Prejudice Jane says, 'our mother' to Lizzie

*to differentiate between people of the same name who are not relatives we say, 'my Joe' and, 'your Joe' (insert appropriate name)--you pick which one according to who has the closest relationship