Halsey K (2002) Percy Bysshe Shelley and Theories of Language: A Discussion. Keats-Shelley Review, 16, pp. 22-30. http://www.ingentaconnect.com/content/maney/ksr/2002/00000016/00000001/art00004
First paragraph: In 1811, Shelley wrote to his grandfather, 'language is given us to express ideas - he who fetters it is a BIGOT and a TYRANT.' This connection between freedom of speech and political liberty remains a constant factor in his often-conflicting ideas about language. Although Shelley nowhere makes explicit a theory of language, there are, throughout his works, intriguing references to the different ways in which language works: as political tool, as imperfect means of communication, as the visible or audible manifestation of the sympathy between souls, as veil which both hides and reveals beauty and truth, as system imposed on Chaos, as conduit (however imperfect) to the Divine. Notwithstanding the paucity of his explicit comment on the period's linguistic debates regarding 'the real language of men' or the arbitrariness of language, Shelley makes dogmatic statements on the subject of language which suggest that he was familiar with a number of different linguistic theorists and theories. The Defence of Poetry (1821), though nominally a manifesto for poetic language, sheds interesting light on some of Shelley's beliefs about language in a more general sense.
P.B. Shelley; Defence of Poetry; Poetic voice; Linguistic theory
Keats-Shelley Review: Volume 16