Research comparing bilingual and non-bilingual approaches has been highly controversial, but most reviewers at least agree that bilingual approaches are no less effective than English-only instruction.
Children who are speakers of languages other than English are typically taught to read in one of two ways. Some are taught in their native language and then transitioned to English at some point after first grade. These bilingual programs also provide English as a second language (ESL) instruction to build students' English skills. The alternative is to teach in English but provide support to help children succeed. Students would typically spend time with an ESL teacher, but would be taught in English from the outset.
The National Academy of Sciences report strongly cautions that more research is needed to identify characteristics of both effective bilingual programs and effective English-only programs.
With that caution in mind, however, available evidence suggests that children ought to be taught how to read in their native language while acquiring oral proficiency in English and then subsequently be taught to extend their skills to reading in English when the proper conditions are in place. These conditions include having a teacher who is fluent and literate in the student's native language and having textual and other material support for instruction in that language. In addition, the literacy level of the home is shown to be a strong influence in the effectiveness of bilingual programs.
In general, principles of effective instruction for bilingual classes are no different from those for monolingual English reading as long as the second language is an alphabetic language.
Principles of effective instruction for non-bilingual programs are also similar to those for monolingual English reading, except that teachers need to make adaptations to make the content comprehensible. For example, many teachers use a technique called Total Physical Response, in which children learn English words by acting them out or by seeing the teacher do so.
ESL teachers should align their activities closely with those of classroom reading teachers, so that they help children with the specific language skills needed for success in the mainstream classroom. ESL teachers themselves often teach the reading class. It is important to avoid a disconnect between ESL and other instruction. The guiding principle should be that the content of ESL and other supplementary services should be driven by whatever children will be held accountable for.
Systematic attention to vocabulary and syntactic development is of critical importance for all English language learners.