Family communication ; Critical period (language acquisition) ; Alter (Einfluss auf Spracherwerb) ; Age (influence on language acquisition) ; Age of acquisition; AoA; Sensitive period (language acquisition) ; Alternation (biling.) ; Language shift (biling.) ; Sprachwechsel (biling.) ; Benefit (biling.) ; Advantage (biling.) ; Überlegenheit (biling.) ; Cognitive gain (biling.) ; Bilingual education