“…Many papers have analysed the positive and negative transfers that can take place between signed languages and learning written English (e.g. Mayer and Wells, 1996;Mason, 1997;Mayer and Wells, 1997;Wilbur, 2000;Johnston, 2002), to a large extent inspired by the theory of linguistic interdependence (Cummins, 1991); others (e.g. Singleton et al, 2004) have discussed this issue in the context of hearing bilingual learners exposed to two different oral languages or exposed to a signed and an oral language, as in the case of hearing people born to deaf parents (Fabretti et al, 1998).…”