Why don't we use any auxiliary when answering phone calls? Would it be wrong if I used the auxiliary? ▪︎ Hello, George speaking. ▪︎ Hello, George is speaking.
"George is speaking" would sound weird, because you could be saying that about someone else.
You'll find people say:
- This is George speaking
- You're speaking with George
But, 'George speaking' is perfectly correct.
You asked why we are omitting the word "is"... simply put, the way people answer the phone doesn't necessarily follow English grammar. In 1970s Britain, a common way to answer home telephones was to just say the name of your town (which identified your telephone exchange) followed by your phone number. Other people would use the family name and simply say something like "Smith residence". The idea was to announce where the phone was located so that the caller knew they had reached the correct number.
Also worth noting is that, if someone asks the person answering "may I speak to George", George may simply reply with one word "speaking". This is acceptable telephone etiquette.