Sign language ; Laterality; Sinistrality; Lateralization ; Hand preference; Linkshändigkeit; Handedness ; Neuroanatomie; Neuroanatomy; Spiegelneuron; Mirror neuron; Neurophysiology ; 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 ; Taubheit; Deafness