People just don't talk like that any more. He's speaking from the top of his throat, just below his nasal passages.

This is the lawgest banjo in the woyld, ya see kid?

He had me at kangaroo gut.

There's a giant up in Appalachia who's looking for his banjo.

0:28

In other words, it's a bass guitar.

Upright basses don't have frets and it does have a sound chamber. He's also playing bass on it.