Viennese way of saying “Hello” like the Italians say “Ciao” and the Germans use “Tschüss” or the French say “Salue”.
Short from to say: I am sorry, but I did not hear and/or understand what you just said. If you don’t mind please be so kind and repeat all again.
(estimated time of departure): after serious considerations and to my best current knowledge I would like to inform you that this might be the time of (my) departure.
(estimated time of arrival): after serious considerations and to my best current knowledge I would like to inform you that this might be the time of (my) arrival.
Please be so kind an proceed with what you have just started, intended or suggested to do.
(will comply): I will do all the needed to achieve exactly what you have asked me to do.
I do agree or confirm exactly what you have told or written to me.
I don’t agree with what you have just said and/or I don’t like and/or I don’t think that you are right with it.
(Markus Lehner): Mr. Oskar Klein, working for the Ford Motor Corporation in the US, always signed “OK” when he approved a new car leaving the production line, but since I am not Mr. Klein I confirm or agree to certain requests with my own initials. For me personally there is another reason to use “ML” as my signature, but that’s again aviator’s language…