The heart of the COMMUNAL system is the Genesys systemic grammar of English. Genesys contains about 600 grammatical systems, and is therefore of broadly similar size to Nigel. All other systemic generators (apart from those which are directly based on Nigel) are much smaller.
A small fragment of Genesys, extracted and modified to be free-standing as a coherent and fairly complete (within its stated coverage) mini-grammar for English modal and auxiliary verbs, was published as an appendix to [Fawcett 1988]. This mini-grammar, which is described in Chapter 5, was used as the basis of the demonstration prototype system for interactive Japanese-European generation described in Part II.