A new ELL student who arrived to the United States at the beginning of the school year was put in a bilingual program. The ELL student made academic growth in both L1 and L2 throughout the year. Which of the following explains the student's academic growth?

• A. The student experienced cognitive development in L1 which transferred to L2 academic language
• B. The student grew primarily from immersion in English
• C. The student benefited only from classroom vocabulary drills in L2
• D. The student’s growth was due to external tutoring in L2 only

Answer: (A)

The main idea here is cross-linguistic transfer: skills and knowledge learned in one language can support learning in another. In a bilingual program, a student’s cognitive development in L1 builds strong concepts, problem‑solving abilities, and literacy strategies that can be applied when using L2. When a learner has solid understanding and reasoning in their first language, they can transfer that foundation to academic language in English, helping them grow in both languages, not just in one.

That’s why this option is the best: it acknowledges that growth in L2 comes not only from practicing English in isolation, but from the underlying cognitive and linguistic development already taking place in L1, which then facilitates L2 academic language.

The other ideas focus only on English exposure or isolated activities (like drills or tutoring) and don’t account for how L1 development can positively influence L2, nor do they explain growth in L1 itself.