Dual language acquisition; Bimodal language acquisition; Spracherwerb (biling.) ; Language acquisition (biling.) ; Bilingual language acquisition ; Alternation (biling.) ; Language shift (biling.) ; Sprachwechsel (biling.) ; Sprachattitüde; Linguizismus; Linguicism; Prestige; Monolinguale Ideologie; Monolingual ideology; Sprachliche Unsicherheit; Linguistic insecurity ; Multilingualism; Polylingualism; Plurilingualism ; Second language acquisition in children; Kindlicher Zweitspracherwerb; Child second language acquisition