Syntactic development; Morphological development; Morphologie (Spracherwerb) ; Syntax (Spracherwerb) ; Grammatical development ; Critical period (language acquisition) ; Alter (Einfluss auf Spracherwerb) ; Age (influence on language acquisition) ; Age of acquisition; AoA; Sensitive period (language acquisition) ; Spracherwerb und neurologische Entwicklung; Language acquisition and neurological development; Sprache und Denken (Ontogenese) ; Language and thought (ontogenesis) ; Cognitive development; Language acquisition and cognitive development ; Kindersprache (Sprachverständnis) ; Children's comprehension of language; Language comprehension in children ; Interimsgrammatik (Spracherwerb) ; Lernervarietät (Spracherwerb) ; Learner variety (language acquisition) ; Interlanguage (language acquisition)