re : 6 . 1100 , disc : uniformitarianism , re : 1086 ; sex / lang dick hudson 's observations on us use of 's on ' but not 'd aughter ' as a vocative are very thought-provoking , but i am not sure that it is fair to attribute this to " sons " being " treated like senior relatives " . for one thing , we do n't normally use ' brother ' in this way any more than we do 'd aughter ' , and it is hard to imagine a natural class comprising senior relatives and 's on ' but excluding ' brother ' . for another , there seem to me to be differences here . if i am not imagining a distinction that is not there , it seems to me that the senior relative terms are used in a wider variety of contexts , e . g . , calling out from a distance to get someone 's attention , and hence at the beginning of an utterance , whereas 's on ' seems more natural in utterances like ' yes , son ' , ' hand me that , son ' than in ones like ' son ! ' or ' son , help me ! ' ( although perhaps these latter ones are not completely impossible ) . alexis mr