Longitudinal study ; Phonemik (Spracherwerb) ; Phonetics (language acquisition) ; Kindersprache (phonet./phonem.) ; Child language (phonet./phonem.) ; Spracherwerb (phonet./phonem.) ; Language acquisition (phonet./phonem.) ; Phonological development ; Second language acquisition (psycholing.) ; Case study (second language acquisition) ; Australia (English language in) ; Australien (engl. Sprache in) ; English in Australia ; Vietnamese