Another lot of good information - thank you all.
I'm still wondering about that break of the voice. How does it work and also:
It can be done on purpose. Men can sing at higher pitch than their normal voice would allow by that. Women can't but this trick or a similar one can also be used without leaving your normal vocal range, and this can be done by women as well, e.g. for yodeling but also with quite normal lyrics. (@§$% - I'm hearing an example from some radio at least twice a week, but I can't tell you the title of the song nor the artist.) This technique allows for changing the pitch much faster than by normal singing; it's like switching rather than adjusting and also back and forth. The only difficulty is exactly hitting the intended pitch - that's the art.
Uhm - Joan Baez also once did it in a recording of 'Brand New Tennessee Waltz' - you know "...at the bra-(NOW!)-and new Tennessee...".
Can you figure out what I mean? I'd love to be able to manage that myself.