Halliday & Matthiessen (2014: 387):
… it is a general principle of linguistic structure that it is the experiential meaning that most clearly defines constituents. Interpersonal meanings tend to be scattered prosodically throughout the unit; while textual meanings tend to be realised by the order in which things occur, and especially by placing of boundaries. These are very general tendencies, worked out differently in every language but probably discernible in all.