Halliday & Matthiessen (2004: 453, 454):
It is possible to ‘report’ a saying by representing it as a meaning. This is the ‘reported speech’, or ‘indirect speech’, of traditional Western grammars; … But the principle behind this hypotactic representation of a verbal event is that it is not, in fact, being presented as true to the wording; the speaker is reporting the gist of what was said, and the wording may be quite different from the original … This is not to suggest, of course, that when a speaker uses the paratactic, ‘direct’ form he is always repeating the exact words; far from it. But the idealised function of the paratactic structure is to represent the wording; whereas with hypotaxis the idealised function is to represent the sense, or gist.