The diagnosis of semantic—pragmatic language disorder (SPLD) has been the subject of a number of research studies over the last two decades. Classification and diagnostic debates, while illuminating, have done little to develop tools to improve services to these children. In this paper, two children whose communication difficulties are suggestive of an SPLD diagnosis but who have differing profiles are studied. Using existing models of psycholinguistics and pragmatics to guide assessment and intervention, the diversity of language and social communicative behaviours that are covered by the label SPLD are exemplified. Consideration is given to whether the term SPLD is appropriate for both children or whether Bishop's revision of the diagnosis to ‘pragmatic language impairment’ might be more useful. Methods of intervention and evaluation for semantic and pragmatic deficits in these two cases are described. It is argued that existing tools can enable accurate explanation and modelling of the communication of children with SPLD and that there is a role for intervention studies in helping to refine those tools, to improve therapies and to understand the nature of the condition more fully.