Common Underlying Proficiency
Theory proposed by Jim Cummins (2000) that knowledge of a concept in a primary language promotes the transfer of that knowledge into a second language (Freeman & Freeman 2004). Beyond promoting knowledge transfer, Freeman and Freeman argue that there is an interdependence between knowledge in a first language and learning a second language. If you have an understanding of what romance is, you are better equipped to understand the Spanish equivalent, románico. The CUP is a cognitive approach to L2 acquisition, supports the idea that being bilingual is a cognitive advantage, and that knowledge in a primary language provides a foundation for learning a second language (Díaz-Rico & Weed 2010).
The characteristics of the Common Underlying Proficiency theory strongly support bilingual instruction practices for emerging and proficient ELL students alike.
Separate Underlying Proficiency
Alternative theory to CUP which argues that proficiency in English is separate from proficiency in a primary language, and that content and skills in a primary language to not transfer to English language learning (Díaz-Rico & Weed).
The CUP theory supports English-only instruction as the most effective way for ELLs to learn the language since L2 proficiency is separate from L1 proficiency.