Dialogeröffnung; Dialogkonstituierung; Summons (discourse analysis) ; Conversation opening ; Form of address ; Institutional communication ; Helpline; Support; Counselling (communication situation) ; Mobile radio; Mobilfunk; Walkie-talkie; Voice over IP; IP-Telefonie; Telephone (language behavior) ; Australia (English language in) ; Australien (engl. Sprache in) ; English in Australia