Vocative case marks a noun whose referent is being addressed.
(http://www.sil.org/linguistics/glossaryoflinguisticterms/WhatIsVocativeCase.htm 17.11.06)
Vocative case marks a noun whose referent is being addressed.
(http://www.sil.org/linguistics/glossaryoflinguisticterms/WhatIsVocativeCase.htm 17.11.06)