Family communication ; Kindersprache (pathol.) ; Child language (pathol.) ; Specific language impairment; SLI; Dysgrammatismus (Kindersprache) ; Dysgrammatism (child language) ; Handicapped language acquisition ; Dual language acquisition; Bimodal language acquisition; Spracherwerb (biling.) ; Language acquisition (biling.) ; Bilingual language acquisition ; Second language acquisition in children; Kindlicher Zweitspracherwerb; Child second language acquisition