Text consists of structured content. Do readers reflect that structure in their production? A system is under design to map the content pattern of a given text, sentence by sentence, thus locating major and lesser topic boundaries. The system depends on word frequency and distribution in that text, and on the recognition of synonyms and other forms of reference, which establish links betwen text segments. Acoustic tools help to identify significant variations in reading performance, and these can then be interpreted in terms of the text structure. Material for the present paper consists primarily of four passages, each read by three speakers; about an hours' reading in all. The passages are structurally independent excerpts from much larger works. All of the sentences were randomized together and read as one list, and then each passage was read in original form. A study based on duration measurements, indicates clear agreement among speakers as to the locations where reading speed changes occur: e.g., in sentences of transition between major topics, and at points of salient semantic shift. However, the nature of the change increase or decrease in speed is highly speaker dependent.