I've often wondered about how the human voice, especially a boy's voice, can remain recognizable after a kid has gone from childhood to adulthood.
After all, the vocal cords grow thicker, the voice box for boys tilts and drops, and the shape of the face changes, and with it the whole oral cavity. And yet the voice is the same, even though it's not the same. And of course there are strong vocal resemblances in families, no doubt because we are again talking about the shape of the face and the bone structure and so on -- the dimensions and the qualities of the musical instrument. Robert Walker Jr. ("Charlie" in the notorious Star Trek episode) sounded uncannily like his father (the slimy and malevolent Bruno, in Strangers on a Train). There's a strong family resemblance too between Dick Van Dyke, his brother Jerry, and his son Barry, and between Noah Beery (Rocky in The Rockford Files) and the big lug Wallace Beery, his uncle. Sometimes I hear an actor and I say, "He's GOT to be related to so and so," and that happened the other day when I "heard" George Sanders on the old Perry Mason show, but I looked and said, "Wait a minute," and sure enough, the actor was one Tom Conway, George Sanders' brother.
Imagine, then, that you live on an island that was settled by a few dozen families 250 years ago. Everybody's at least a distant cousin to everybody else ... and they all sound alike. And there are certain characteristic tonal qualities that we associate with this or that ethnic group. If you go to Italy, you will inevitably meet some guy or some kid who sounds like Tony Danza, with that husky-breathy voice, that Marlon Brando had some of, and Aldo Ray had a lot of.