The Interdependence Hypothesis (Cummins, 1979) states that ‘’literacy-related concepts and skills in first and second languages [...] are interdependent’’ (Cummins, 2013). It acknowledges the importance of prior language knowledge, as well as cognitive processes, in learning languages.
The main idea behind this theory is that when learning a language, students acquire a foundational bank of language skills and competencies, learning strategies and knowledge that they can draw upon for transferring when they learn subsequent languages. Cummins calls this shared language base the Common Underlying Proficiency (CUP).
Common Underlying Proficiency (CUP)
The CUP has frequently been illustrated by the dual-iceberg (Cummins, 1980, 1981). The iceberg image shows that, like the tips of icebergs, languages may seem distinct on the surface, but they share a larger common base on the conceptual level. "In other words, although the surface aspects (e.g. pronunciation, fluency, etc.) of different languages are clearly separate, there is an underlying cognitive/academic or literacy related proficiency from one language to another." (Cummins, 2008)
In the Classroom
Both surface features and underlying conceptual elements of languages may be learning goals for transfer. The potential for superficial transfer is just the tip of the iceberg and these obvious language similarities and differences may lead to both positive and negative transfers. The CUP containing underlying conceptual language features, skills and strategies which are common to all languages has the potential for more significant and enduring transfer. Attending to the deeper conceptual understanding that is common among languages leads to the reflection and metacognition necessary for language learning. Research has shown that this transfer is positive for the learner and contributes to developing competency in both languages.For more information, refer to Teaching for Transfer.