It is proposed that conflict is an almost inevitable outcome, when, as in dementia communication, the delicate relationship between linguistic processing and pragmatics is upset. This relationship has been little researched, even though much is known about the two components in isolation. Making particular use of key observations and claims from the papers in this special issue, a macro-conceptualisation of the dynamics of conflict and aggression in the dementia context is developed. It is proposed that the cognitive and linguistic processing problems experienced by a person with dementia (PWD) can undermine her capacity to manage her spoken output in the way necessary to match the situational pragmatics, resulting in failure to achieve her interactional goals. The mismatch will create internal dissonance that may be expressed as aggression. Importantly, caregivers will also experience dissonance when their communicative agenda is not fulfilled. This may happen when their expectations of the situational pragmatics (e.g., old versus new information) are contradicted by the behaviour of the PWD. Here too, the dissonance may result in aggression or conflict. Modelling the mechanisms of ‘Communicative Impact’ (CI) offers a way to capture the relationship between processing and pragmatics and to examine how speakers attempt to resolve the dissonance. The CI model gives insights into how the risk of conflict in interaction between people with dementia and their caregivers might be minimised.