Diapix’ (van Engen et al., 2011, Baker and Hazan, 2011) is a problem-solving ‘spot the difference’ picture task used for eliciting spontaneous speech interactions between two participants. Participants have to try and work out what 12 differences there are between their pictures without seeing their partner’s picture. The pictures are carefully designed to elicit certain vocabulary items. This task has been used with children aged 8 years and above as well as with adults aged up to 85 years. To get a ‘clean’ recording for each participant, the diapix task can be done with each participant seated in a separate sound-treated booth and communicating via headphones.