Erstspracherwerb; First language acquisition; Ontogenese; Language acquisition ; Syntactic development; Morphological development; Morphologie (Spracherwerb) ; Syntax (Spracherwerb) ; Grammatical development ; Kindersprache (Sprachverständnis) ; Children's comprehension of language; Language comprehension in children ; Learnability (of language) ; Lernbarkeit (von Sprache) ; Spracherwerb (Theorie) ; Language acquisition (theory of) ; Poverty of the stimulus-argument; Theory (language acquisition) ; Intonation (sentence) ; Satzakzent; Sentence intonation ; German