“…Existing SDS include DEAL (Wik & Hjalmarsson, 2009), DISCO (van Doremalen, Boves, Colpaert, Cucchiarini, & Strik, 2016), ISLAND (McGraw & Seneff, 2007), SCILL (Seneff, Wang, & Zhang, 2004), and SPELL (Morton & Jack, 2005) (see Bibauw et al, 2015, andEskenazi, 2009, for detailed descriptions of these and other programs). By focusing on SPELL, Morton et al (2012 ) illustrate how such programs generally work. For example, 'in the About Train Times scenario, the virtual character asks the learner some questions about the departure and arrival times of trains in Great Britain.…”