On an interesting note my twin brother went through a phase when we were about 14 where he could imitate some celebrity voices like Rich Little does. Not just the mannerisms but the sound too. But later he wasn't able to do it.
On a related funny note with our first job as grocery store clerks at abut 15 years of age, with the money we earned, we bought a cheap cassette tape recorder that seemed to be off a little and we swore up and done it made us sound like John Denver. Not long after that the tape recorder just died.
He has a lower register than mine in the baritone range while I am closer to a tenor. I want to get him to do some songs with me and I'll do harmony.
Thank you for the comments so far!