A text is not simply a grammatical entity. It is created with the purpose of conveying meaning, so that the choice of grammatically possible words is further constrained by the particular communicative purpose of the writer. Each word depends in part on the words, or collocates, around it to realise one of its range of potential senses, and to disambiguate it where ambiguity exists.
Lexical cohesion is another feature of text which makes clear the message within it.
The relationship between the sentences in a text is signalled by grammatical, lexical and other features. Lexical repetition is one form of lexical cohesion, whereby words are repeated across the sentences of the text in a way which reminds the reader of the thread of the argument. So here again, surface word pairings in text are capable of leading the reader to something deeper. In this lecture, I shall present some of the ways in which such surface collocational and cohesive information is being incorporated into automated systems in order to discover new facts about meaning in the English language. The main intellectual thrust of the Unit's work over the last ten years has been towards developing ways of improving the understanding and description of the English language as a textual reality.