In this invited Afterword Matthiessen positions this volume as the third step in a series of books introducing students and colleagues to Systemic Functional Linguistics (SFL) – following on from the general introduction in Matthiessen and Halliday (1997/2009) and the introduction to formulating system networks in Martin, Wang and Zhu (2013). It also positions the work on English, Spanish and Chinese in this volume in relation to work on other languages, much of which has been curated and/or mentored by Matthiessen. In addition this afterword reviews a number of key issues arising in relation to language description based on SFL. These include the paradigmatic orientation of system descriptions, cryptogrammatical reasoning, trinocular vision (from about, from roundabout and from below), metafunction (ideational, interpersonal and textual), rank and functional language typology.

Chapter 4 explores mood systems and structures. It concentrates on paradigmatic relations – and the ways in which these can be motivated in the grammars of English, Spanish and Chinese. This chapter foregrounds questions about the nature of functional language typology, when confronted with the diverse structural realisations of mood in three different languages. It highlights the need to focus on system rather than structure, on higher ranks rather than lower ones and ultimately on discourse semantics rather than grammar by way of establishing comparable ground whenever languages are being contrasted and compared.