A little more context
The goal is not to choose between a familiar language and learning additional ones. It is to make understanding possible while widening a learner’s linguistic opportunities. That requires more than translating a textbook: teachers, materials, and education policy all need to support the approach.
Language policy shapes whose knowledge is easy to express and whose participation takes extra effort. UNESCO’s guidance treats linguistic diversity as a resource for education, rather than simply a problem to manage.
The practical question is how to support familiar languages alongside additional languages. Local context matters: a single formula cannot capture every classroom, community, or teacher’s needs.