Proper vs. common, e.g. 'John', which normally occurs whithout a proclitic determiner in English, and 'boy', which normally occurs with some determiner: 'the boy', 'a boy', 'this boy'. - Nida (1949), a pag.166
This category in English is syntactically pertinent, but is indicated morphologically in many languages. - Nida (1949), a pag.166