Factor 3 - Early exposure to accessible language through sign is beneficial to language acquisition.
To guide our team in identifying evidence shown to support linguistic competence, we followed definitions of evidence described in Evidence-Based Practice in the Early Childhood Field (Buysse & Wesley, 2006). In this book, specific to the field of early childhood, evidence includes: 1) "the best available research" (based on research studies, evaluations, objective measurements of child progress, and systematic literature reviews), 2) practitioner experience or professional and/or family wisdom (based on personal observation, experience, professional or expert consensus, position papers, policy statements and professional judgment), and 3) consumers' values and beliefs, which include personal beliefs, concerns, and expectations of consumers (parents and professionals).
Factor 3 Evidence Summary
The evidence supporting Factor 3 centers on:
- the benefit of using visual language to establish early timely language foundations and minimize language delay,
- the beneficial role of sign language in the development of spoken language, and
- the potential of hearing families to acquire the competence to facilitate their child's development of visual language.
For children who are deaf or hard of hearing and do not have full access to quality spoken language, evidence documents the benefits of early accessible visual language and the adverse neural and performance consequences of delayed exposure to language when it is not accessible (Baker, 2011; Morford & Mayberry, 2000; Grosjean, 2008). Evidence also indicates that the development of a signed language is developmentally time-locked to early childhood, similar to spoken language, stressing the importance of stimulating development of signed language early in a child's life. (Baker, 2011; Mayberry & Eichen,1991). Further, the literature documents the important role of using visual input as a substitute or supplement to audition in creating a shared language between parent and child, as visual language has the potential to support family-child attachment, which is an indicator and predictor of current and future development (Meadow-Orlans et al., 2004).
Evidence also contradicts some prevailing thinking regarding use of sign as an impediment to spoken language development (Wilbur, 2000; Yoshinaga-Itano, 2006). The evidence does not support this and does support the beneficial role of sign language in the facilitation of and transition to spoken language (Grosjean, 2008; Baker, 2011; Yoshinaga-Itano, 2006). It also supports the use of sign language prior to cochlear implantation to benefit establishment of early language foundations and to support and assist in the transition to development of spoken language (Yoshinaga-Itano, 2006). Neuro-scientific evidence confirms that facilitation of linguistic milestones in both spoken and visual modalities can occur at the same time in a child's development without harm to development of language in either modality based on the brain's capacity to develop two languages/modalities (Kovelman et al., 2009; Petitto et al., 2003; Petitto et al., 2001). Further review of literature supports the benefit of approaches inclusive of both American Sign Language and spoken language (bimodal, bilingual approaches) for children who will be using or have cochlear implants, discussing how these approaches have the potential to foster early language through the child's vision while also stimulating the child's audition (Mitchiner, Nussbaum, & Scott, 2012; Nussbaum, Scott, & Simms, 2012).
To dispel concerns that hearing families cannot effectively learn and use signed language to facilitate their child's language development, evidence suggests that hearing families, provided with appropriate supports to facilitate signed language, can effectively learn and use signed language to enhance their child's learning (Spencer, 2004). The literature discusses multiple strategies and resources to support development of family competence in visual language development so they can facilitate their child's visual language acquisition (Bailes et al., 2009; JCIH, 2013; Spencer & Harris, 2006).