A Common Misconception
Teachers who discover the Science of Reading sometimes worry: does this mean phonics instruction in English only? Does adopting structured literacy mean abandoning bilingual education?
The answer is no — and understanding why reveals something remarkable about how children's brains actually process language.
The Transfer Principle
Dr. Jim Cummins, one of the most cited researchers in bilingual education, established what he called the Linguistic Interdependence Hypothesis: skills acquired in one language transfer to the other. The brain does not build two separate reading systems — it builds one cognitive reading system and applies it to multiple languages.
This means that a student who develops strong phonemic awareness in Spanish carries that skill directly into English. A student who learns to identify word roots (like "geo" from Greek, meaning earth) understands that same root in both *geography* and *geografía*. A student who masters comprehension strategies — inference, main idea, text structure — uses those same strategies in both languages.
Dual language and the Science of Reading are not in tension. They are multiplicative.
What It Looks Like in Practice
In a dual language Science of Reading classroom:
Phonemic Awareness is taught in both languages, and teachers explicitly make connections between them. Spanish phonemic awareness transfers easily to English because Spanish is highly phonetically consistent — once students master Spanish phonemes, English is less overwhelming.
Phonics is taught systematically in both languages using each language's own phonics patterns. Spanish phonics is simpler and more consistent than English phonics — making Spanish an ideal foundation. Students who can decode in Spanish learn to decode in English faster than students who have no home language literacy.
Fluency develops through reading in both languages. Students who read fluently in Spanish are likely to become fluent English readers more quickly than students who only read in one language — because fluency is partly a general cognitive skill, not purely language-specific.
Vocabulary is where bilingual students have a profound advantage. English has over 10,000 cognates with Spanish — words that look similar and mean the same thing. A student who knows *información* immediately recognizes *information*. A bilingual student is building two vocabularies simultaneously, with constant cross-language reinforcement.
Comprehension — the ultimate goal — transfers most completely of all. A student who has been taught to identify the main idea in a Spanish text can do the same in English. A student who has been taught to make inferences in English brings that same skill to Spanish. The strategies are universal.
The Evidence
Research on structured literacy in bilingual programs shows:
The Practical Message for Teachers
If you teach in a dual language classroom: use structured literacy practices in both languages. Teach phonics explicitly in both. Build vocabulary in both. Teach comprehension strategies in both. The transfer will happen — and it will accelerate learning in both languages.
If you teach in a monolingual English classroom with bilingual students: honor and leverage the home language. Pre-teach vocabulary in the home language. Explicitly teach cognates. Encourage students to think in their home language first when encountering difficult text. This is not a workaround — it is scientifically grounded practice.
If you are a school leader: the question is not whether to do dual language *or* Science of Reading. The question is how to implement both, together, for every student.
The two most powerful research-backed programs in education are not competing for space in your school. They are waiting to be combined.