ESP; English for academic purposes; EAP ; Aeronautics (technical language) ; Aviation (technical language) ; Occupational language behavior ; Mobile radio; Mobilfunk; Walkie-talkie; Voice over IP; IP-Telefonie; Telephone (language behavior) ; English as international medium ; Second language acquisition (pragm.) ; Zweitspracherwerb (pragm.) ; Interactionist hypothesis (second language acquisition) ; Conversational analysis (second language acquisition) ; English