ELL learners: The early development of two languages is best approach

The Foundation for Child Development has issued a new report:
PreK-3rd: Challenging Common Myths About Dual Language Learners:

The most current scientific research suggests that the development of two
languages from a child’s earliest years has specific impacts on a variety of
cognitive functions discernable as early as seven months of age that are persistent
throughout childhood and may even offer some protection from symptoms of
Alzheimer’s.

Enhanced executive function abilities such as working memory,
inhibitory control, attention to relevant vs. irrelevant task cues, and mental or
cognitive flexibility, as well as improved language skills, have been linked to early
bilingualism when proficiency in each language is roughly balanced. These
abilities have been portrayed as the biological foundation for school readiness,
providing the platform upon which children’s capacities to learn (the “how”)
educational content (the “what”) depends. It has been found in multiple studies
that there is a bilingual advantage when comparing monolinguals and bilinguals
on tasks that require selective attention, cognitive flexibility, and certain literacy
skills such as decoding when the two languages have similar writing systems.

Notably, these advantages have been found across all socio-economic, racial, and
ethnic groups, and as noted above, are linked to the level of bilingualism; those
children who had more balanced skills in each language showed greater advantage.