Is literary language a development of ordinary language?

Contemporary literary linguistics is guided by the 'Development Hypothesis' which says that literary language is formed and regulated by developing only the elements, rules and constraints of ordinary language. Six ways of differentiating literary language from ordinary language are tested against the Development Hypothesis, as are various kinds of superadded constraint including metre, rhyme and alliteration and parallelism. Literary language differs formally, but is unlikely to differ semantically from ordinary language. The article concludes by asking why the Development Hypothesis might hold.