Predictions of Individual Differences in the Acquisition of Native and Non-Native Languages: An Update of BLC Theory

BLC Theory proposes that individual differences (IDs) in language proficiency (in both native and non-native speakers) can poorly be mapped on a single proficiency scale. Instead, IDs can best be understood and studied in terms of two fundamentally different dimensions: (1) the cognition of oral language (receptive and productive speech processing) and (2) the cognition of the written language (reading and writing). This paper presents an update of BLC Theory placed under a non-nativist, usage-based, neural-network metatheory of language as a complex system. The paper includes predictions for the absence or presence of IDs in the oral and written domains, separately for native and non-native speakers. The theory predicts that while cognitive factors such as executive functions, non-verbal memory, and intelligence positively affect the acquisition of reading and writing skills in both native and non-native speakers, they do not play a significant role in the acquisition of speech processing in either native or non-native speakers. Contrary to folk wisdom, one does not need to be particularly intelligent to learn to understand and produce speech in a non-native language. Attention is given to typological differences between children’s home language(s) and the standard language(s) of literacy.