> Luxembourg come to mind as natural bi- or multilinguals. Speaking from experience with Luxembourg, their school results (PISA) are average despite sky high t

> Luxembourg come to mind as natural bi- or multilinguals. Speaking from experience with Luxembourg, their school results (PISA) are average despite sky high teacher salaries and a ton of investment into education. Especially STEM results. The more languages Luxembourg adds the worse results become (Portuguese immigrants fare worse than locals).