How do impressionists mimic voices so well?

Question:I mean i was watching Alistair Mcgowan last night and he got me thinking how do all these impressionists do it so well, what techniques are involved to mimic the voice. I know that they get into character but i don't understand how they manage to change there voice

Best Answer - Chosen by Asker: I mean i was watching Alistair Mcgowan last night and he got me thinking how do all these impressionists do it so well, what techniques are involved to mimic the voice. I know that they get into character but i don't understand how they manage to change there voice

Its not just the voice but manerisms, hand guestures, interjections, voiced pauses - everything to do with how someone comunicates. Catchphrases or idioms are all important.
Rory Bremner can impersonate people with just a single sound or movement. He might go "Yeeees" to indicate he's being Jeremy Paxman or notice when he does Gordon Brown he leaves his mouth open and the end of each sentence just as GB does. Getting the voice is the hardest part but its all the furniture I've listed above that make something a great impression.

loads of practice

practice and being able to listen!

practice out loud, record yourself and play back. do this over & over again.

A good ear, like perfect pitch in music, a strong aural memory (do you forget things if you only hear them) and practice recording and listening to their voice so they judge accurately the difference between hearing their own voice reverbing their head vs. the voice of another person coming only through the air. And practice.

It's called talent