Halliday & Matthiessen (2014: 509):
… projection combines with the same set of interdependencies that have been shown to occur with expansion – (1) the two tactic interdependency relations of parataxis and hypotaxis and (2) the constituency relation of embedding.
For instance, ‘We really have to have mandatory child safety trigger locks, and photo license IDs for the purchase of new handguns,’ is projected paratactically by Gore told the crowd. This means that the projection is represented as a quote.
In contrast, she saw one young man open fire after a feud between youths became violent is projected hypotactically by Nakisha Johnson, 17, said. This means that the projection is represented as a report – as something that is dependent on the projecting clause and thus cannot serve on its own. …
In addition to the two tactic modes of projection – paratactic projection of quotes and hypotactic projection of reports, there is one further environment in which projected clauses occur – that of embedding: the witness’s claim that she saw one young man open fire seems plausible.