Syntactic development; Morphological development; Morphologie (Spracherwerb) ; Syntax (Spracherwerb) ; Grammatical development ; Dual language acquisition; Bimodal language acquisition; Spracherwerb (biling.) ; Language acquisition (biling.) ; Bilingual language acquisition ; Transfer (second language acquisition) ; Transfer (Zweitspracherwerb) ; Cross-linguistic influence (second language acquisition) ; Interference (second language acquisition) ; Second language acquisition in children; Kindlicher Zweitspracherwerb; Child second language acquisition ; Indefinite article; Definite article; Unbestimmter Artikel; Bestimmter Artikel; Article ; Gender ; Holländisch; Dutch