Using parental report to assess early lexical production in children exposed to more than one language

A small expressive vocabulary in young children is considered to be the first warning signal of delayed language development (Ellis and Thal, 2008). In turn, early language delay may be the most obvious indication of later language impairment (Paul and Roth, 2011). However, the immense variability characterising language development in young children makes it difficult to predict the evolution of early language difficulties (Ellis and Thal, 2008). For instance, substantial proportions of late talkers have been reported to spontaneously overcome their language learning difficulties completely (e.g. Dale et al., 2003; Rescorla et al., 2000). In contrast, a series of research findings attest to late talkers’ continuing speech and language difficulties through the preschool years (see Paul and Roth, 2011). Difficulties with language development may continue to manifest themselves in a subtle form in adolescence (Rescorla, 2009, 2013; Tomblin, 2008) or may even become more persistent and marked with increasing age (Rutter, 2008). It is therefore best to consider limited word production in young children as a ‘red flag’ for potential specific language impairment (SLI) (Ellis and Thal, 2008), the latter being diagnosed when children’s persistent difficulties in language are discrepant with broadly typical abilities in other areas of cognitive, physical and socio-emotional development.