the reader has to go back to the previous stretch of discourse to establish what This refers to. So, reference is a device which allows the reader/hearer to trace participants, entities, events, etc. in a text. One of the most common patterns of establishing chains of reference in English and a number of other languages is to mention a participant explicitly in the first instance, for example by name or title, and then use a pronoun to refer back to the same participant in the immediate context. Those languages which have number and gender distinctions in their pronoun system are less constrained in using this cohesive device, since different pronouns can be used to refer to different entities within a text with less possibility of confusion.