Bimodal language acquisition; Language acquisition (sign language) ; Spracherwerb (Gebärdensprache) ; Sign language (language acquisition) ; UG; Universal grammar ; Representation (phon.) ; Phonological representation ; Metalinguistic awareness; Phonologische Bewusstheit; Phonological awareness; Focus on form (language teaching) ; Sprachbewusstsein; Linguistic awareness ; Spracherwerb und neurologische Entwicklung; Language acquisition and neurological development; Sprache und Denken (Ontogenese) ; Language and thought (ontogenesis) ; Cognitive development; Language acquisition and cognitive development ; LAD; Spracherwerbsmechanismus ; Minimalist program; Generative theory of language