Erstspracherwerb; First language acquisition; Ontogenese; Language acquisition ; Case study (language acquisition) ; Kindersprache (pathol.) ; Child language (pathol.) ; Specific language impairment; SLI; Dysgrammatismus (Kindersprache) ; Dysgrammatism (child language) ; Handicapped language acquisition ; Metalinguistic awareness (in children) ; Phonics (teaching of) ; Phonologische Bewusstheit (bei Kindern) ; Phonological awareness (in children) ; Focus on form (language teaching) ; Sprachbewusstsein (bei Kindern) ; Linguistic awareness (in children) ; German