What's the point? The role of punctuation in realising information structure in written English

The main claim of this paper is that punctuation marks, in conjunction with spaces between words, function to provide visual rather than auditory cues for information structure in written English. INFORMATION STRUCTURE is defined here as dividing the flow of discourse into units, each containing a newsworthy element, and in contrast to the Systemic Functional systems of REFERENCE and THEME. A model of how these three systems interact is further supported by evidence from the historical development of reading and modern studies of the process of fluent silent reading. Reading silently does not require physical articulation and so written text is constrained by the saccading eye rather than the need to draw breath. The silent reader uses punctuation marks as a guide in a saccade to focus on the end of a clause which provides a non-arbitrary location for New Information.