Healey et al. use experiments with chat dialogues to test the hypothesis that language co‐ordination is driven by ‘running repairs’. They replace signals of understanding such as “okay” with weaker, ‘spoof’ signals like “ummm”, and replace specific requests for clarification like “on the left?” with signals that suggest a higher degree of misunderstanding like “what?”. The latter manipulation causes participants to switch rapidly to more abstract forms of referring expression.